Lode Runner P8? Might be simpler, might be harder.

[Steve Nickolas <lyricalnanoha@usotsuki.hoshinet.org>]

Here's some stuff I dug up while tweaking around with Lode Runner.  You'll 
need a disk image of the game itself for it to work very much, and I'm 
still poking around to find stuff.

http://xtra.usotsuki.info/lrrl.zip

"postmortem.bin", which is a RAM dump, is the most important piece here. 
There is also a packed version that loads as a file.  They only contain 
the code, not the data.

Well, I know how the data is stored, and it's easy as cake.

http://www.brutaldeluxe.fr/crack/LODERUNNER.DSK

The data is stored in DOS Order, starting from Track 3 Sector 0, one level 
per sector.  Level "151" is blank, and "152-154" contain the 3 levels that 
are looped in the demonstration.  155 contains garbage and that's end of 
data.

Being that I made this editor - http://xtra.usotsuki.info/lodehax.dsk.gz
it may be possible to compact the code further by removing the one in the 
program. (Mine uses Flex Type.)

-uso.