I’d love to do an analysis of the PC version of Ultra’s Teenage Mutant Ninja Turtles game.
Maybe I will… eventually.
But this video focuses specifically on a game-breaking mistake by the developer - Something
the Internet refers to as “The Impossible Jump.”
To explain, let’s examine the NES version first.
In level 3, you reach a building where you climb down into the sewers, make a few jumps
over some water, and eventually climb out via a ladder on the opposite side.
In the PC version – a port that is pretty faithful in terms of game progression at least
– reaching the same point in the game presents you with THIS challenge: Jump over a large
gap of water with a low ceiling just over your head.
Despite the added ability in the PC version to jump higher by pressing down before jumping,
the layout in the sewer doesn’t give you the workspace to clear the jump.
As this jump is required in order to progress, it essentially breaks the game.
Progression is possible via cheating as there is a code that allows you to walk over just
about anything on the overworld map.
If you glance at the comments of various other videos, blogs or forum posts on this subject,
some remember getting past this jump without cheating.
Others specifically state that they didn’t have a problem and mention that they played
the European version – Teenage Mutant Hero Turtles.
At this point, March 2018, it seems the general consensus is that it was broken in the American
release and fixed for the European release.
There is a bit of irony in the fact this would remain unfixed in America as it was developed
in Canada.
Was it ever fixed in America?
Could you dial-up the USI BBS for a patch or receive a floppy disk containing a fix in the mail?
DOS preservation today seems to simply lean on whatever copy was uploaded to an abandonware
site years ago.
Are there different versions?
Exhibit A: My copy of TMNT for DOS.
Version 2.0!
Could it be that a later version was released that fixed the impossible jump?
Does this very floppy contain a shorter, jumpable gap?
No.
It does not.
If I go by file dates, it looks like various files across the game were updated since what
I will assume is the original 1989 date, however the L3-06 files – the files that make up
our level with the problem – don’t seem to be included in the newer files with a mid-March
to mid-April 1990 datestamp.
A side-by-side comparison of the American and European gameplay show more than a simple
jump correction.
Graphics have also been altered.
Comparing the data of the level files indicates quite a difference.
Of course, these resource files appear to use a compression algorithm of sorts – so
even minor changes between the two versions would appear to have a major difference after compression.
Well, I want to know what is over there.
What if the level isn’t even finished?
What if there is something written on the wall by the graphic artists?
What if even more of the level is broken?
WHAT IS OVER THERE??
Let’s find out.
If we can cheat and walk across the grass to get to the next area, we could do as much,
enter the sewer from the opposite side and work it backwards until we reach the impossible
jump.
The problem with this is the cheat requires you to press A-S-D-F-G-H at the same time.
The keyboard for the system I am using doesn’t have the necessary rollover to press six keys
at once.
So - let’s take a different approach.
One nice thing about the DOS release is the ability to save your game.
If you get into trouble, just reload.
It is a legitimate savegame as well.
It isn’t checkpoint based – your score, inventory, and location are all retained.
The savegame file itself appears to be uncompressed, so perhaps it can be edited easily…
Thanks to the savegame provided by the website scary-crayon.com, we can load the exact spot
of the jump.
If we make a backup copy of the savegame file before playing, load the save in-game, walk
a little to the left and save again, we now have two files for analysis.
Doing a hex comparison of the two savegames, we can then figure out which pieces of the
file have changed.
After some quick trial and error, location CC would appear to hold the Turtle’s position.
Using this, I manually increased this value until Donatello got past the jump location.
Success.
Loading the savegame places Donatello to the right of the jump.
So… let’s continue!
Aaaand I think we’ve hit another snag.
Ha!
I tried a few times, couldn’t make this jump either, and ended up editing the savegame
AGAIN in order to move Donatello over a bit more and get past the second jump - or at least impossible for me.
Finally, we can exit the sewer.
In the future it might be possible to patch the level so that both jumps can be made.
In the meantime, cheating by way of walking over the grass or using a hex editor to manually
skip past the level would seem to be required in order to continue.
Alternatively, those of you with the American version may wish to seek the European version
or somehow acquire the L3-06 files from the DATA subdirectory of the European version
and drop them into the American version.
I tried this, and it worked.
And of course the ultimate, easier solution is to simply play the NES version.
Which you probably want to do anyway.