Bug/Glitch Verification

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CapnClever
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Bug/Glitch Verification

Post by CapnClever » Wed Apr 09, 2014 3:35

(EDIT: I'm going to make this a catch-all thread for any bugs or glitches I find that I either can't reproduce or do so reliably.)

At KeenWiki there's this entry filed under Keen3 Bugs:
Keen 3 Bugs wrote:Fly without cheating

It is possible to fly in the air without using a cheat. Just press jump and then fire at almost the same time. You will waste a few bullets, but it is good for getting to tough places when you do not want to cheat.
I spent a good while trying to get anything remotely looking like flying to work in Keen3 using the procedure described above and failed entirely. Has anyone here done this before and, if so, could you describe how to make it work? Depending on the direction of flight, this bug could be very useful in the speedrun of this game. (I also don't know why it would apply only to Keen3. Maybe it's version-specific?)

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Post by CapnClever » Wed Apr 09, 2014 22:23

Found something undocumented and unfortunately completely unexplainable right now. It's in, all of places, Keen Dreams.

When I was practicing the speedrun route, Apple Acres was a huge pain because I'd make it into the lower-left corner where you grab Boobus Bombs and then miss the jump to get the pogo. Sometimes I missed it a few times in a row, sometimes the cart would just kill me as I frantically hopped. Ironically enough, my current record makes a mistake earlier in the level and coincidentally synced up my jumping to the pole with the cart being a stepping stone to get to it, so I didn't have to worry about it then.

I looked into this discrepancy further, mostly because I'm confident I can grab a pole almost all of the time, even if it's invisible, and even if I can trouble with poles for other reasons. It turns out that, somehow, Keen's jump can get stunted. It's not a lot by any means (perhaps one or two pixels) but it's JUST enough to miss that pole, which is probably the only reason I'd ever notice it.

This are some details that I've tried to glean after trying things out in that little mine shaft, but please note that none of them are certain. I really wish they were, but I yet to consistently reproduce this bug. (Note I'm using shareware version 1.01, in case it was inexplicably fixed in other versions.)
  • It seems to carry over until Keen is killed, similar to key storage. Meaning I could get this to happen, immediately reload, and then have it happen again regardless.
    Keen doesn't stand at a different height when his jump is stunted.
    It doesn't appear to have anything to do with horizontal momentum nullification when you're next to a sheer vertical edge (which you can amazingly pull off in that area, as small as it is.)
    It doesn't appear to have to do with the cart. (I usually jumped over it pretty clearly in my testing.)
    It doesn't appear to have to do with buffering jumps, or buffering a moving jump into a standing jump, or vice versa.
    It doesn't appear to have to do with variable height jumps, although the gradation of jumps is small enough that it could be a really particular sweet spot.
    It has nothing to do with the jump into the area beforehand. (I made a save specifically after the jump in case it could be isolated to strange pole behavior, since the fastest way to reach the area is by jumping off a pole.)
Steps to (maybe?) replicate:
1. Go to Apple Acres
2. Fall yourself into the lower-left area with the Boobus Bombs and the 1UP
3. Save at the very right side
4. Exit game, reload save (just to get rid of any weird memory floating around)
5. Make your way to the left, jump from the ground into the flower pot and 1UP while grabbing for an invisible pole
6. If you grab the pole, reload and repeat step 5.
7. Keep trying until you never grab that pole.

The stunted jump is noticeable, too. A full-height jump from where the pole is will obstruct Keen's eyes at its apex; a stunted-height jump will not. Please let me know if someone can also make this happen and let me know I'm not crazy.

I honestly don't know if this would affect anything else: apparently you can just barely grab that pole and, since it's a pretty secret area and you don't have to grab it from the ground, I really doubt they were so lazy as to put a similar jump in the game (unless it also involves a cart). If anyone can make a custom map with a custom tile that has very obvious height markers, we could play around with this and figure out the cause.

---

I actually have a third glitch that I just remembered, but I'm gonna hold off because triple-posting seems rude.

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Post by CapnClever » Fri Apr 11, 2014 22:35

Okay guess I'll just triple-post. I could technically lump them all in the same post, but they all sort of warrant their own so I'd rather keep 'em seperated.

This one is really simple but also really subtle. I was learning the Keen4 route and I got to the point where you need to do a pretty crazy couple of jumps at the top of Isle of Fire. The setup is incredibly precise to make sure you don't die falling into a ground-fire, so after failing at getting it myself, I watched Cosmo's current record run of the game. To my complete surprise, he did the same setup but had different results! Boggled, I searched for an answer and isolated the difference in our movement to the position Keen arrives at when climbing the ledge just before the jumps. Seems absurd, right?

Here's the zinger: Keen moves to a different location immediately after he's done climbing a ledge depending on the version. In v1.0 he moves a tiny bit back from where he appears to climb to; in v1.4, he's much better at lining up with the climbing animation. I haven't gotten around to checking this in the other games but I wouldn't be surprised if it applies in those as well. It would certainly explain why that really cramped ledge spot next to the spinning hazards on top of Keen5's Energy Flow Systems is there at all: in the version I run (1.4) he dies if I try to climb it, but he might remain alive in 1.0.

While I'm posting, I have a question for the modders and mod creators here. Since I'll be working on running a number of mods, are there any bugs/glitches you recall that were targeted and removed as the result of general patching? I was trying to get the pogo ceiling clip to work in Yorphius II DX with no luck, which got me thinking it could have been decidedly fixed. It'd be convenient to know this ahead of time so that I have a good idea of what I should and shouldn't bother testing for "unintended shortcuts". (Or maybe there are some topics describing the content of oft-used patches? That alone would be great to have.)

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Post by Levellass » Sat Apr 12, 2014 8:05

I have in fact undertaken a study as to the ledgeclimbing behaviors and can confirm that the specific amounts of horizontal and vertical adjustment differ between the two versions.

The Keen Vorticons pogo glitch is most often fixed by simple graphic patching of the pogoing sprite. In general good mod design removes glitches better than patching. (The door-exit bug for example is taken care of by not putting door tiles on doors you don't want Keen to enter.) And in fact there are several 'glitches' that have been invented during modding. (See ValoKeen where in the second-to-last level you can open a door AND flip a switch at the same time.)

In general if a glitch cannot be done in every level it will likely have been removed by good level design. Otherwise it should still be there. (Exception: Impossible bullet, but that's easy to check.)


Commonly used patches are usually simple ones, changing the initial ammo, adding\removing pogo, sound and music patches. The Keen wiki contains a number of previously used patches, most of which have only been implemented once.
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Post by CapnClever » Tue May 27, 2014 22:11

Here's another glitch from Keen Dreams, which I have dubbed the "grape stomp". I don't understand the exact causes, but circumstances of a grape falling while Keen barely falls from a ledge (barely in this case meaning that he's exactly against the ledge of the platform from which he fell) results in Keen achieving a instantaneous maximum velocity downward. You can see this occur here. I've tried to get it to work on other ledges, as well as on the same ledge without the grape falling, but it really seems to have to do with the grape descending while you do, hence "grape stomp".

It might apply to other enemies that can achieve downward motion, such as Squashers, Tomatooths, and possibly Carrot Couriers. It's also rather difficult to pull off because of the necessity to be really close to the ledge as you fall (simply holding the directional key isn't enough). I'd like to know if anyone manages to get this to work consistently for them, and if they can make it work anywhere other than the place shown in the video. Depending on the required circumstances, this might technically exist in the Galaxy games but cannot occur because of ledge-grabbing.

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Post by CapnClever » Sat Jun 28, 2014 8:12

Was practicing Perilous Pit (that is, a level in Keen4) and I suddenly exited the level after entering the big passageway taking you to the council member. Upon entering, Keen did his walking-into-door cycle but didn't actually move into the door, and instead of going to the door's exit, Keen was teleported somewhere else for a frame before the level ended (presumably somewhere out of bounds, hard to tell from the frame though). Sounds kind of like Keen5, right? Turns out I did some kind of weird precision trick where the bounder next to the blue key pushed me off the pole and down the shaft. (Normally if you're pushed off, you just land back on the surface.) I debug-tested this hypothesis and yes, the bounder pushing me off the pole caused Keen to use the door differently.

What does this mean? It means you can do the "secret exit glitch" in Keen4. Not that it sends you anywhere useful, mind you, but it would seem that the code wasn't game-specific towards this. It's also from version 1.0, not sure if that necessarily matters. (Which probably means you can use it in Keen5 v1.0 as well, using amptons.)

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Post by CapnClever » Sun Jul 06, 2014 23:19

Oh man even more. This one's technically quite old but I don't believe anyone's ever tried to verify it.

So in Keen5, there's the secret level, and on that secret level there's a secret exit. That secret exit is only supposed to be doable on Normal or Hard difficulty (and, indeed, the fuse that activates said exit doesn't break normally). However, someone managed to show off a Keen5 speedrun on Easy some five years old (see this video) that uses the same route as the expected route. This means breaking the fuse and, in this video, it happens.

I remembered seeing this video a while back when I was searching for optimal routes for this game, but couldn't reproduce it myself and dismissed it for some editing or cheat-like maneuver. However, yesterday I was curious about it again and, sure enough, I was able to make it happen. Cut to some emulation and frame-advance and I think I know why it works.

Although Keen is shooting, the trick itself has nothing to do with the bullet. I noticed that, when shooting downwards, Keen is able to fall farther "into" the fuse: maybe the lower gravity is ignored when you're shooting, I don't know. The point is that Keen can clip slightly into the fuse and then activate his pogo perfectly, thereby breaking the fuse from the inside. It's possible that this limitation wasn't actually intended and was only the consequence of not being able to jump high enough to reach terminal velocity normally, or maybe related to the "goplat" bug. Either way, it's definitely doable albeit very difficult to pull off.

I was having trouble coming up with reproducible results, however. Granted, advancing frames doesn't appear to affect the timing (as it would in the Vorticon games), but I've yet to get it to work after, for instance, saving the game. Could just be that's it's too hard to pull off consistently to measure this, however.

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Post by Nospike » Mon Jul 07, 2014 11:29

I recall someone mentioning that the unbreakable fuse on easy is a bug and not supposed to be that way.
Edit: Managed to shoot-pogo it on the second try, doesn't seem that hard... :p
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Post by Captainkeen » Tue Jul 08, 2014 17:43

Fly without cheating

It is possible to fly in the air without using a cheat. Just press jump and then fire at almost the same time. You will waste a few bullets, but it is good for getting to tough places when you do not want to cheat.

I spent a good while trying to get anything remotely looking like flying to work in Keen3 using the procedure described above and failed entirely. Has anyone here done this before and, if so, could you describe how to make it work?
1. Turn on god mode
2. Press and hold ctrl
3. Press alt while in the air
4. Repeat step 2 and 3

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Post by Fleexy » Tue Jul 08, 2014 18:09

CapnClever wrote:Fly without cheating
Captainkeen wrote:1. Turn on god mode
While that might be a wonderful way to fly with cheating, we're looking for a way to do it without such things. ;)

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Post by chrissifniotis » Wed Jul 09, 2014 5:42

Fleexy wrote:While that might be a wonderful way to fly with cheating, we're looking for a way to do it without such things. ;)
I was gonna say, I nearly fell on the floor laughing. :mortlol :lol

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Post by CapnClever » Mon Aug 11, 2014 16:01

Found a way to freeze the game! I'm getting too good at this.

Lifewater Oasis in Keen4 has an open top. This might be really rare, I dunno, they usually don't give you the option to reach the top and find out. With an Impossible Pogo Trick off the highest platform available, you can just barely skim this top, such that Keen is slightly not on screen. Everything's fine so far. However (and thing is something I'm sure they didn't expect) if you shoot upwards at the apex of your jump, the game stops working. No input allowed, no response from the computer (or emulator) itself, nothing. Music still plays, doesn't help much.

My guess is that is has something to do with spawning the bullet somewhere that doesn't exist, or somewhere that is technically two places at once (since there's evidence that the top and bottom of the map can cause wraparound as seen during Impossible Bullet Trick manipulation). I really have no idea other than that hunch. It's pretty dang rare to completely freeze the game, especially in a vanilla setting.

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Post by Roobar » Mon Aug 11, 2014 18:57

The reason for this is that the top of the level is consisted of only one array of tiles, whereas the top of the level of all the other levels is with two lines of solid blocks. And it was missed by the author of the level when it was done back then (probably Tom Hall's fault).

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Post by KeenRush » Tue Aug 12, 2014 20:25

wiivn is most likely right. Anyway, cool -- this is the first time as far as I remember I've heard of anyone managing to make Keen crash (without modifying it somehow, as goes without saying). If the level had the ordinary tile border it probably would work right. Interesting. 8)
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Post by Roobar » Tue Aug 12, 2014 21:19

Now THIS might be ground braking! There is a way to get to the raindrops and life water flasks in Keen 4 Level 10: Lifewater Oasis without using cheats after all. Now because of CapnClever statement about freezing the game, I turned on the cheats and tried out that, but then I find out that at a specific place if you bump up into the ceiling, you will teleport down below right in the water! And this proves that it is (still) theoretically possible to get them even WITHOUT cheats. The only thing is that someone should try that jump at that place without cheats. Here's the video:

http://youtu.be/x_cJYA7uKw4
Last edited by Roobar on Tue Aug 12, 2014 21:27, edited 1 time in total.

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