Play the (cross your fingers) really fixed version
of
Crypt of Medea!
by Rubywand
When Laurent Stern posted a request for a working version of this
Sir-Tech classic it was a surprise to discover that, evidently, one
did not exist!
After all these years, the bug in the deprotected version remained
and
users were still getting snagged trying to cross the ravine.
What happens is that, if you are not carrying too much and should make
it
across (by swinging on the rope), the game wipes memory and forces
a reboot.
Fortunately, the reboot is via a brute force jump to Slot 6 ROM code;
so,
locating the wipe & boot routine in memory was fairly easy-- you
look for
a jump to $C600. Once you know where the routine is, you look for places
where the code jumps to or calls the routine and figure out which of
these
is involved in bombing the game when swinging across the ravine. (Substituting
Break instructions for the jumps/calls is one way to do this. You swing
across
the ravine and the program falls into the monitor and you are told
the
location of the Break which sent you there.)
Once it was possible to swing back and forth across the ravine, it seemed
worthwhile to check if the game could be played through to a win.
Well, Crypt of Medea is a pretty decent challenge with lots of
stuff to figure
out. (It took a couple hours to make it to the ravine with the rope.)
So, I resorted
to looking for a walkthrough. GameFaqs.com
happens to offer a very good one
written by Douglas Cameron.
One more odd wipe & boot snag was encountered and fixed. After that,
play
zipped along until near the very end when a weird problem with timing
blocked
the path to victory.
You need to light a bomb, drop it, and get out of the room before the
explosion; but,
there just isn't enough time to type in the needed instructions.. (The
walkthrough
mentions that getting it done is not easy-- and, the walkthrough is
based upon play
using the original disk.) Somehow, the deprotected copy version
had shortened
the time still further.
The fix was to track down the code which sets the time allowed and increase
the
value of a byte. The new period is about 24 seconds on a 1MHz Apple
II or
emulator-- longer than anyone is likely to need.
So, the bomb worked. Within a few moves, I had escaped Medea's dread
crypt and won!
You can download the new version along with a Save disk and docs in
the file
CryptOfMedea_v2001.zip. Let me know if you discover any glitches.
Credits
Besides persons and sites already mentioned, thanks go to Greiner Wolfgang
for his May 1988 article about Crypt of Medea in Computist #55, to
the Apple Bandit for doing the original deprotect, and to Asimov
for maintaining a copy.
Downloads
from GSWV
CryptOfMedea_v2001.zip
(includes docs file)
from Asimov
CryptOfMedea_v2001.zip
(includes docs file)
from GSWV
CryptOfMedea_docs.txt
CryptOfMedea_hints.txt
CryptOfMedea_walk.txt