This is a 1985 commercially released BBC Micro game that was long believed to be unplayable. The manual stated that the objective was to collect the Golden Fleece, and made vague mention of secret passages and also that you would transform from human to gargoyle at night, but didn't state what that would do for you. A solution was finally posted on the stardot forums in 2020, 35 years after the game's release.

The objective is to touch all four prisms on the map to make the fleece and the exit appear, for an any% run you can then just exit, for 100% you also need to get the fleece, which is located near to the game start. Secret passages are required for completion and involve walking into certain walls to get teleported elsewhere within the game. The entire lower half of the map is only available by secret passage.

The full map, by Ed on the Stardot forums is here: https://i.ibb.co/TghJyCM/Nightword-Game-Map-1-0.png note that the screen colours are random on each playthrough so do not match the map.

Notes on bugs & glitches used:

There is no air control, and a fixed jump height of 3 blocks as the human, higher for the gargoyle. Fall damage kicks in at 3.5 blocks and will gradually reduce your health as you fall, making it possible to die before you even hit the ground. There is also a wall climbing mechanic on certain walls, but it's generally very slow and best avoided as you only climb 2 blocks per jump, even as the gargoyle.

Transformation happens approx every 90 seconds, which makes routing choices for a run interesting, some sections can only be completed as the gargoyle, and some are better completed as the human due to his lower jump height = less fall damage taken

The collision detection is limited, for horizontal movement, only two points either side of your hat are checked, this makes it possible to walk through 1 block high walls. For downwards movement, two points at the bottom left and bottom right of the sprite are checked, for upwards two points near the top/centre are checked and the horizontal movement points are different. This is abused heavily in the run. The exact pixels checkes are shown in this GIF by SteveF on the Stardot forums, demonstrating an easy way to softlock yourself!: https://stardot.org.uk/forums/download/file.php?id=84839

All sprites in this game cause damage, even collectables like the prisms. There is also a bug on some room transitions where sprites are not properly removed and can still cause damage while being invisible, sadly it does not extend to actually collecting the prisms

The damage sound effect causes game slowdown due to filling the computer's sound buffer and having to wait for it to empty before the next sound can be loaded in. Disabling in-game audio does not fix this, for which I am secretly grateful as having to submit a silent run would suck. All in-game timers (i.e. the sun/moon clock used for transformation) are slowed down by this, so damage affects RTA timing only.

Room transitions are slow, and are best minimised

It is probably impossible to do a glitchless run of this game

Room-specific notes: Number (Letter on Ed's map) Top colour/Bottom colour

1 (A) B/W: By clipping through the floor in the bottom left, we can leap towards the exit from a lower height and avoid a delay caused by hitting the room transition while jumping up to the final platform. Normally you would enter room 2, fall immediately back into 1 and then position for exit

2 (B) R/B: Nothing special here apart from a bit of minor wall clipping. The triple room transition is unavoidable

3 (C) G/Y: Intended solution is a vertical wall climb, or a bounce of the back of the harpy, but it is faster to jump onto the wall eater, take some damage and then frame-perfect jump (4px down), catch the wall and jump left

4 (E) B/G: Deliberate floor clipping to slightly lower the height of the harpy so we can bounce off its back and take less damage

5 (F) B/C: Bats have the ability to block your horizontal movement which in this jump would make you fall, frame perfect jump needed to bypass that, I beleive this works by keeping your collision detection pixels above the bat sprite. Also the jump at the exit shows a common technique to avoid delays due to falling vertically on stairs

6 (G) R/M: Prism 1. A lot fiddlier than it looks, with carefully positioned jumps to avoid long vertical falls in favour of diagonal falls. It is also important that that final jump out of the room be done as the human as the gargoyle will jump too high and trigger a room transition at the wrong height, meaning you need to exit and return to walk through the floor and skip part of room 7 (F).

7 (F) M/R: As we exited 6 (G) with a floor clip we can fall straight down. We take extra damage as the sprite for the prism in room 6 is not removed fully by the game. This is unavoidable

8 (H) B/G: Prism 2. Three frame-perfect jumps are needed to get the prism optimally, it is necessary to clip at least 3px into the second top platform to make the jump onto the final platform, and then frame-perfect to get off the platform. I did mess up that last jump but we were quite far ahead of schedule (see prism 4 room) so this time loss makes no difference to overall run time. On exit we use a carefully positioned jump to avoid triggering a double room transition as for some reason that also avoids the sprite re-use bug which would cause us damage in the next room.

10 (E) Y/B: By clipping through the floor we avoid the need to jump and take damage from falls / the harpy

11 (C) G/R: Actually a lot easier than it looks, just hold the jump key and hit directions as appropriate

12 (D) B/R: Prism 3. Easy to lose a lot of time here by getting caught on the bat or the statue.

13 (A) G/B: This is the start of the Lower World. Statues cause more damage to the human than the gargoyle, so it's important to get through them. The final jump needs a different position depending on which you are. In a good run you should still be the gargoyle

14 (I) G/Y: This is why we jump on the previous room, by clipping into the left hand wall we change one long fall into multiple short falls, saving 9.5 blocks worth of fall damage

15 (J) R/G: Several time-saving floor clips to get through this section, and one frame perfect jump through a diagonal gap that is a run-killer if got wrong. This hits the only optional secret passage in the game, taking us to the health regen room.

16 (N) Y/C: The top-left item is a health regen but collecting it also increments the game success counter and triggers a bug where the entrance to the Prism 4 room closes. This is because each prism adds 20% to your success counter, the health adds 10% and the entrance only opens at exactly 60% success.

18 (M) C/B: The final jump from this room must be done as the human as the gargoyle will leave the room too high and end up stuck in the wall. Also in the next room the final jump must be performed as the gargoyle, so you cannot leave this room until the sun clock is just past the prism (visual indicator). Despite having a small amount of time to kill we still have to take the damage from that fall rather than taking a longer, safer route. This is because the game is only able to detect collision with one sprite at a time and the longer route means the bad can reach the prism, rendering it uncollectable.

19 (L) B/M: The exit route is chosen to manage the height of the harpy, such that when we jump onto its back it is high enough that our head collision points do not hit the ledge and we can jump through it. We start the jump as the human, but jump height is not calculated until you hit a cap, 3 or 6 blocks, so transforming mid-jump increases the cap.

20 (K) R/W: This is one of those rooms that is just messy, and very easy to get stuck. Wall climb is intended but frequently fails and gets you stuck. Wall climbing is slow as the gargoyle as you jump up six blocks, but then fall down four. However because we hit the ceiling the wall climb is cancelled and we remain at the tim.

21 (I) B/M: The final big run killer. You lose a lot of health on this fall and there isn't much you can do about it that won't cost you time.

22 (J) W/C: You lose a lot of health to the fall and the monster. If you don't have enough health to attempt his then abandon your any% run and go for 100% instead as you need to come the same way to get that health regen!