General info:

Difficulty Levels:

There are four difficulties: Easy, Normal, Hard, and Realistic. Compared with Normal, AIs take 25% more damage on Easy. The player takes 25% more damage and AIs take 25% less damage on Hard. The player takes 75% more damage and AIs take 50% more damage on Realistic. AIs also have decreased accuracy on Easy and increased accuracy on Hard. Difficulty doesn't make much difference most of the time when speedrunning this game because most of the enemies are ignored and healing items are plentiful. Playing on Realistic makes most enemies take fewer pistol shots to kill, but ultimately, the most important effect is probably how easy it is to destroy the missile batteries in the WTO hangar.

Jumping:

Jumping adds to your vertical speed in this game, so there are several ways of jumping extra high. The simplest is to jump while running up a slope. Another is to bump into the edge of something you can stand on on the way up, allowing you to jump again without landing and increasing your speed. It's also possible to jump into a corner and get stuck just long enough for the game to let you jump again (sometimes repeatedly), but this isn't very reliable. As in many games featuring Havok physics, you can also "fly" by repeatedly jumping off an object, then grabbing it and releasing it again.

Tagio discovered that hitting jump and a direction key at about the same time causes you to jump higher than normal. This is why I often stop briefly before a jump. The closer together the presses, the higher the jump. If jump is pressed first, you go straight up, except for a bit of air control. If the direction key is first, you keep your horizontal speed.

With these tricks it's possible to get out of bounds in outdoor areas, but it's rarely helpful. There's often nowhere to stand on the wrong sides of walls and you can't pass through walls from the wrong side. So generally you just fall out of the map and die.

Conversations:

I sped through conversations by hitting the escape key as fast as I could. Each press skips one character's entire line of dialog. After I was past the last place it would have been useful, I discovered that the right mouse button does the same thing, which would have let me get through them faster. These controls aren't affected by the in-game keybindings.

The fade-in, fade-out, and delay before you can select a line when you have a choice can't be skipped, so I avoid conversations that aren't required whenever possible. I discovered that NPCs can't start conversations while drawing or holstering their weapons, so firing a gun to startle them at the right time allows you to run past them. If they don't have a weapon or it's already drawn, I simply shoot them to make them hostile. Conversations also generally won't start while people are shooting at you, which is useful for skipping conversations with holocom terminals.

Infolinks:

Infolinks are one of the biggest obstacles in speedrunning Invisible War. Characters are constantly sending you these messages and you can't open the menu or leave a map while one is playing (except for a few cases). The maps are very small due to the limited hardware of the original XBox, so infolinks can delay you from leaving in many cases. One second after you activate the trigger to travel to another area, the game checks to see if an infolink is playing. If so, you have to wait a bit before you can try again. I used a lot of trial and error to figure out when to activate each trigger to leave as soon as the infolink finishes. I also took advantage of segments where I had extra time to collect items, allowing me to avoid losing any time for that.

To add insult to injury, certain controls don't work during the first second after an infolink starts. You can't select or use inventory items (including weapons), toggle biomods, or interact with things (pick up objects, initiate conversations, push buttons, open doors, etc.) during this time.

Fortunately, I found a few ways to avoid unnecessary infolinks. This is responsible for a large fraction of my improvement over Tagio's run. In open areas it's often possible to go over the triggers. If you trigger an infolink just as another queued one is starting, one of them may be skipped. Also, I discovered that infolinks can't start while NPCs are speaking unique lines of dialog. So if you trigger an infolink during one of these dialogs you can leave the map or save and load before it finishes, skipping the infolink. This is the only reason I used mid-level saves. The rest of my segments were autosaves.

If you trigger more infolinks while one is playing, they're added to a stack, so the most recently received one plays back next. Certain pairs of infolinks have a fraction of a second gap between them during which you can leave the area, skipping the rest. I only discovered this towards the end of my run, but I haven't found anywhere earlier in the game where it's usable.

Almost the only things that can interrupt infolinks are conversations. Some won't start until the current infolink finishes, but others will interrupt it. This is great if the conversation causes you to leave the map, but otherwise the infolink will be added to the stack again to play after the conversation finishes.

Notes on routes and specific segments:

2, Tarsus Recreation: I mess around a bit because I'm stuck in the locker room for a while. I discovered much later that it is possible to block the door from closing, but the objects I had been trying to use, like the big rectangular trash bins, almost never work. For some reason, the broom works much better if you throw it so the handle sticks through the doorway. That would have saved about 8 seconds. The jump against the column is a stuck-in-a-corner jump. It was very difficult to get the double jump and get over the railing but under the overhead beam. In retrospect, it would have been easier and maybe a bit faster to throw an object into my path on the way in and use it to object fly with on the way out. Jumping up to the balcony isn't really faster than taking the stairs, but it skips a conversation with Billie Adams, leaving her standing zombie-like in the elevator.

4, Biomod Laboratory: Using the 3 biomod canisters to max out speed enhancement is the obvious choice. If I'd known about it at the time, this would have been a good time to use the multiple pickup glitch found by Amoirealinge in the original Deus Ex. If you bind interact to the scroll wheel, you can pick up certain types of objects several times before they disappear. In Deus Ex, it only works with ammo and stackable items that you already have some of in your inventory. In Invisible War, it works with ammo, biomod canisters and weapon mods. In Invisible War you can also get a huge number of pickups by saving while aiming at an object and repeatedly pressing interact while loading the save. Although it would have made things easier to have gotten cloak, thermal masking, and maybe other biomods here, it wouldn't have actually saved much time since I never had to slow down appreciably to avoid damage.

Seattle: This is the most complicated section of the game to plan a route for. You have to complete a mission for either Donna Morgan or Lin-May Chen, then free either Ava Johnson's helicopter or Sid Black's jet. Tagio discovered that if you get the evidence from the Inclinator for Chen, but report to Morgan at the air terminal instead of returning to the church, then Morgan gives you the objective to go to Mako and Ava sends you the code to the hangar by infolink. Unfortunately, she doesn't send you the hangar code if you go to Emerald Suites for Morgan, so you can't avoid going to Lower Seattle. I considered stopping by the Greasel Pit to get the code in a conversation to avoid the infolink, but it seemed to take the same amount of time and cost the grenade in the air terminal. One possible route that might be faster is to collect some money along the way, complete Chen's mission, bribe Sofia Sak to release Sid's jet, and hire him to take you to Mako. However, this would mean Sid would take you from Mako to Cairo and drop you inside the arcology, which is awful. So ultimately I used Tagio's route.

10, Inclinator Facility: Chen's infolink when you reach the upper level usually doesn't start unless you kill some of the thugs on the lower level. Unfortunately, it's required, so I had to keep trying until it worked.

11, Upper Seattle City Center: I tried boosting off the bench up to the upper level, but it didn't save time. I use the pillar to shield myself from the grenade blast, so I hardly have to slow down. In retrospect I guess I could have afforded to jump through the beams, losing half my max health.

13, WTO Air Terminal Hangar: It's only possible to destroy the missile batteries with one grenade on Easy or Realistic. By destroying the batteries and activating the beacon before the first infolink finishes, I trigger the final infolink next, allowing me to talk to Ava one second after it starts and skipping several more infolinks. Since I had a bit of extra time, I was able to run a bit closer than I would have on the shortest route, making the grenade throws merely difficult rather than virtually impossible.

15, Mako Ballistics Interior: The most obvious mistake in Tagio's run (and a major reason I decided to try to improve it) was getting the Mag Rail here. I was planning to use my multitool on the weapons lab door, but jumping into the vent turned out to be a bit faster, if rather tricky. I assassinate the scientist with a grenade just before the first infolink ends. This saves over 40 seconds versus getting the Mag Rail. The locked door starts to open, presumably to explain how the two guards who just spawned got in. Nice try. Shooting the glass sets off the alarm, opening the door to the security station. Morgan calls me a mercenary, which is funny because I don't get paid or rewarded for anything I do in the entire run. I love how the bot is just sitting next to the explosive crate when I come down the stairs.

16, Mako Ballistics BioLab: This segment took hundreds of attempts because of all the little things that could go wrong. I had to startle the scientists so their dialog wouldn't delay Morgan's infolink. I could have segmented to skip it on the way in, but it would have triggered on the way out because the scientists were panicking by then. I get cloak here, making nonrobotic enemies even easier to ignore. I move my consumables to the hotkeyed slots so I can use them while running. This doesn't affect the timer, but saves real time.

Cairo: In order to leave, you have to talk to Dr. Nassif in the ApostleCorp facility. To get the code, you have to go to either the Cairo Tarsus Academy, or Bay 24 in Arcology Air Terminal. Both of those require a code from North Medina. Tarsus Academy turned out to be slower and more out of the way.

17, South Medina: Passing through a trigger box around where you start here should initiate a conversation with Ava. However, I was sometimes able to avoid it, apparently due to lag. Sadly, I generally wasn't able to replicate this in other areas with similar triggers or by saving right next to triggers. This is probably the easiest and most useful place to get out of bounds in the game.
To make up for the last segment, I got this amazing one in about five tries with a very lucky boost off the railing (I think).

18, North Medina: I get the hangar code from the datapad, but I still have to talk to the Omar to get an Arcology pass.

23-25 Arcology Air Terminal: Because I got the code from the datapad, I don't have to talk to the receptionist. This let me use the auditor's dialog to skip an infolink from the Omar on entering Bay 24. I wasn't quite able to get to the terminal on the balcony in time, so I had to segment. Talking to the SSC guard ends the message from the Arcology Chairman, giving me the code to the ApostleCorp facility, but delays the infolinks from the Omar and Chen so I can segment again. That way I can leave as soon as I get to the exit.

Trier: You have to talk to Tracer Tong to get the code to the Black Gate Lab. Then you have to talk to Her Holiness in the lab, fly to the Templar Compound to recover the stolen module, and return to the lab. I took the sewer route to the lab both times, allowing me to avoid visiting the SSC station for the gate code.

34, Nine Worlds Tavern: I have to close the door behind me to avoid a conversation with Ava. Tong bribes me with a biomod canister. I upgrade cloak to save energy.

36, Black Gate Ruins: The toxic goo only checks your proximity every so often, so with speed and good timing it's possible to avoid damage from it. The greasels are busy shooting at the rats, so I just have to hope they don't hit me. The box flying is only a few seconds faster than taking the nearby ladder, but looks very cool.

37, Black Gate Laboratory: I take advantage of the infolink to grab the control room code for next time. I realized later that the control room door is destroyable, so killing a couple guys for their grenades would probably have been better. I'm not sure why the Templar with the shotgun doesn't shoot me on the way out. Maybe he just reacts slowly, or I'm too close for him to hit me thanks to the long barrel.

43, Templar Compound: A slope jump plus multiple edge jumps results in this ridiculously high jump, which avoids having to go about 2 seconds out of the way.

44, Templar Church: The second infolink usually doesn't play unless or until you kill one of the guards by the lectern. However, it's required for Ava to appear, so I had to retry until it worked.

49, Black Gate Laboratory: There are too many things in the way of jumping down the shaft or walking around the ladder, so I just start climbing down it and immediately let go. It's possible for an NPC to open the control room door at just the right time and then get out of the doorway, but it's extremely rare. A concussion grenade might also be slightly faster. The infolink that triggers part way into the control room has to finish before the teleporter can activate, so I time my jump so I'll be in it when it activates. There's another infolink, but the teleporter can interrupt it.

50, Shackleton Ice Shelf: I save a bit of time by getting the bot to rocket the unlocked door. My last grenade takes out the flame turret and the locked door.

51, JC Denton's Sanctuary: Okay, this one is a bit complicated. I had been planning to get the energy cell in the replica of Maggie Chow's apartment, but I wasn't sure it wouldn't cost time. Fortunately, I ended up having enough energy without it. I wait a bit before teleporting to the replica MJ12 cloning lab because moving out of the corner there causes Billie to appear and she'll initiate a conversation the next time an infolink ends. It's probably possible to damage her before Dumier's infolink ends, but I didn't manage it. I kill her mainly to avoid an infolink from Saman in UNATCO Ruins, but this may not actually matter. Still, it's faster to kill her because apparently that prevents her infolink from restarting if it's interrupted, so it's OK to talk to JC Denton before it finishes. I think this is the only case where you can kill someone while they're sending you an infolink.

I discovered during this segment that the first attack against Billie while she's friendly deals 50% extra damage, which doesn't seem to be the case for anyone else. I also discovered that the sniper rifle has separate cooldowns for scoped and unscoped shots. Scoped shots seem to do about twice as much damage as unscoped shots against most targets and it would normally take two scoped headshots to kill Billie on Realistic. But thanks to the bonus I'm able to use a scoped shot, then an unscoped shot right after it. The bonus also means she can be killed by a single concussion grenade, which might be even faster, but I didn't have any left. If you attack her from farther away than I did she'll disappear when her health is low. Maybe she has cloak too?

For some reason, talking to JC before his infolink starts causes Dumier's infolink to start immediately after the conversation. Normally it doesn't trigger until you're a bit past the doorway on the way out. JC's infolink would play after Dumier's, but I manage to leave the level in between them. This attempt was the first time this happened even though I'd tried it a lot in other places. I thought it might be a one-in-a-million fluke, so I kept it despite the fact that I could have killed Billie and skipped through JC's conversation a bit faster. It's still pretty good though.

56, South Medina: Again, you start in a trigger box for a conversation with Ava. I skip it again, but it was much rarer this time. So I kept this segment despite getting stuck briefly trying to walk through the passage in the wall.

59, Order Mosque: I love how these guys are no threat whatsoever because they always use their grenades first. If you listen, you can hear the guy who yells "Kaboom!" frag his female ally. Oops.

60, Arcology Levels 107 - 108: This infolink can be avoided if you do something differently earlier in the game, but I'm not sure exactly what. Maybe finishing the interrogation of Dr. Nassif or talking to Dumier after rescuing Her Holiness? Whatever it is, it's probably not worth it. Killing Klara Sparks actually results in a longer infolink.

61, Arcology Air Terminal: I had considered killing or reviving Paul here to alter the infolinks on Liberty Island, but due to tricks I found there it didn't really matter. So I choose the fastest option here.

Liberty Island: There are four possible endings: siding with JC Denton and ApostleCorp, Luminon Saman and the Templars, Dumier and the Illuminati, or Leo Jankowski/the Omar. All of them except JC's ending require killing JC (sometimes twice) and at least one other faction leader. The only one that might be close to as fast as JC's is the Omar/rogue ending (kill all the leaders), since it doesn't require you to enter UNATCO Ruins. I tested it and it could be done surprisingly fast, but not quite as fast as JC's ending, even before I found some new infolink skips for that one.

62, Liberty Island West Side: Pretty much everybody tries to talk to you here and on the next map. Staying away from the Statue avoids an infolink from JC. It's possible to circle around the UNATCO entrance to avoid Tong's infolink and use the armored Templar's dialog to skip Dumier's that triggers on entering the statue. However, Saman's is so long that it's faster to trigger Tong's and Dumier's and then exit between Dumier's and Saman's. Around here I realized I had way more healing than I needed and stopped worrying about taking damage. Oddly enough, most of the bots on the island have it in for you and only you regardless of which faction you work for.

63, UNATCO Ruins: Skipping JC's infolink on the last map means getting it here. Fortunately, it triggers near the entrance, so it's practically over by the time I trigger the next one by entering the server room. If I hadn't killed Billie, she'd be waiting for me on Level 1 and I'd have to shoot her to avoid a conversation, which would trigger an infolink from Saman. With my strategy, the timing works out so I can leave between infolinks without waiting long, skipping one last one from Saman. There might be some way of arranging the infolinks, possibly involving strategically interrupting one, so that one ends slightly sooner but still within the range of times it's possible to reach the exit in. I wasn't able to find a better strategy though.

64, Liberty Island West Side: I have to make JC hostile or he'd talk to me when I try to use the machine. I accomplish this by shooting a rocket turret with my pistol at point blank range. Do not try this at home. I shave one last second by saving to show the time .9 seconds before the final cutscene.