Keen 4 Bugs
This page lists all the bugs, odd behaviors and unexpected actions that have been discovered in Keen 4.
In version 1.0 of the game the gems that you are carrying are not included in the save file, thus when a save file is loaded any gems Keen had are lost, possibly causing an unwinnable situation.
Well of Wishes bug in God mode
Often, when two Dopefish overlap and God mode is activated (this is accomplished by entering the Well of Wishes in Hard difficulty level), the game starts to get out of free memory, and all animated sprites (i.e. bubbles) get stuck in the game screen instead of disappearing after a certain amount of time. This eventually crashes the game in low-memory environments.
Bad grammar entering the Pyramid of Shadows
When entering the Pyramid of Shadows, the entrance text reads "Keen move silently in the Pyramid of Shadows" instead of "Keen moves silently in the Pyramid of Shadows".
Not so Invisible
Only certain Keen sprites respond to gravity; if Keen is looking up or down, or hanging from a ledge, he is immune to falling. Thus, if Keen does any of these on a Miragia platform, he can stand on it, even when it disappears. If he is looking up/down, if he then stops when the platform is solid, he can stand on the vanished platform for as long as it takes his "bored" animations to start. So if the blocks start disappearing, quickly grab the ledge of one of them and climb onto it again when it reappears.
Hole in his Head
When Keen is at the top of any pole and facing left, shooting left will display the sprite used for shooting left on a pole, this however is missing a piece of head that is normally covered by the pole, but not at the pole top.
Blue Bird of unhappiness
If you can lure a flying Blue Bird to the right edge of a one tile thick platform (and sometimes walls or thicker platforms), it will get clipped into the platform and not be able to chase after Keen. (God mode helps at least for practice.) It can be freed only by stunning it.
What Lies Beyond
Keen can peek at and past the lower level border under certain circumstances, viz that if the game is saved while he is standing on a moving platform near the level bottom, the screen will be recentered after saving (and whenever the game is loaded), so that he can look down and see not only the level border, but also a bunch of scrambled, random graphics tiles "outside" the level, probably caused by reading memory out of the tile array, resulting in random garbage left by other programs or procedures of the game itself.
The only place this can really be seen is beneath Crystalus, but it works in any other level if platforms are placed right.
In a similar vein, Keen can see what is offscreen by saving his game. This can be done in places like the Pyramid of the Gnosticene Ancients by using God mode and dropping into certain tar pits.
Well of Wishes clipping error
Cave of the Descendents unexpected end
In the Cave of the Descendents, go to the lower leftmost part of the map, where are two elevators. Go down to the second one where has a door that teleport you to another on the top of the map. Enter the door then release the up key and immediately press it again and keep it pressed. It will make Keen enter to door in the top and consequently exit the level. See the video on how this bug happens.
This works because when Keen exits any door, he initially does so standing. In this case Keen can enter the doors before falling. Since the doors have no information plane entry, the game takes this as transporting Keen to (0,0) in the level, which is offscreen and thus lets him exit. If the doors are given a proper value, this can be fixed.
Chasm of Chills door trick
This bug works in a same way the Cave of the Descendents unexpected end -bug does. In the very beginning of the map, fall down from the edge and head right. You'll find three small chasms. Drop in the middle one, and jump trough the wall at the right. Keen will fall right in the front of a door. Press the up key to enter the door, then release the key and immediately press it again. Keep it pressed. Keen will then enter a door mid-air, in another room, and complete the level.
In Lifewater Oasis, when using the F10+J Jump Cheat, if you make Keen hit the ceiling in different places and at different angles, Keen will disappear and randomly reappear somewhere else within the level. In fact, there are at least two places (possibly more) in the ceiling that, if you make Keen jump in these places at the right angles, he will actually reappear in the water where the five Lifewater Flasks are. The interesting thing is that one of these places is right above the highest structure where the big door and the Thundercloud is. If the game designers had created Keen to jump higher or designed the structure to be closer to the ceiling, then it would be possible to take advantage of this bug and get to the Lifewater Flasks without cheating. Unfortunately, once you are there, it is impossible to get back out without cheating. This bug only works when you are at the outside of the level. It does not work in the lower cavern.
Outside the Pyramid of the Forbidden
It is possible to go outside the Pyramid of the Forbidden without using the F10+N clipping cheat. At the beginning of the level, as you are going towards the top of the pyramid where the first Lifewater Flask is, there is a green Dart gun above the flask and there is a small gap in the wall just above the gun. Using F10+G God mode, you can grab onto the ledge where the gap is and it will push you off the screen and out of the pyramid. Then, you save your game and then reload the game you just saved. It will show Keen standing outside the pyramid.
If a creature that normally stays on the ground all the time is somehow forced into the "air", it will appear to spin around like a propellor, without falling down. This is probably because such creatures are programmed to turn and face the opposite direction when they come to a cliff edge, i.e. the next tile is empty air, but when they turn and find that there is "air" on the other side of them, they reverse direction again.
This can be done with Inchworms (in the Pyramid of the Moons) and Poison Slugs (in Sand Yego). In both cases, Keen has to lure the creatures out onto a bridge, and then flip the switch that makes the bridge disappear. When this happens, the normally land-bound creature will find itself in the air, and commence spinning. If a Poison Slug is shot, it will then fall out of the air as per normal. May also work with Arachnuts.
Imaginary pole in The Perilous Pit
In the same room as the Council Members in The Perilous Pit, there is a tile at the right side of the gem-holder which is set to act like a pole even though the tile is empty. Ordering Keen to look down while bypassing the tile will cause him to lag, changing him into his pole-climbing form back and forth into his ordinary running/standing form.
Break the scorebox
In several levels it is possible for Keen to emerge from a door and touch an elder. Since the sprite for Keen appears before the screen moves to the new location, the elder message appears over the door Keen entered.
Due to how Keen moves between doors (As an invisible sprite) the function refreshing the scorebox is not called, meaning that it is blank until Keen does something to change this (Dying, exiting the level, getting something...) This takes a lot of chance to do correctly and can be seen in this video at 5:25