[stella] demo update: PCMSD20.BIN

[Piero Cavina <p.cavina@xxxxxxxxxxxxx>]

Here's a major update of my current demo. There's a much more here, first of
all a backround grid of tiles that must be turned on in order to... (watch
carefully what is going on :)
Again, it was tested only on the three emulators I have, but since there's
some very time-dependent code in it there might be some bad surprise on the
2600.

Now the question is: can it become a good game?! I'm not sure yet... please
send your advices now!
Source code has become a mess after the last changes so I won't be able to
post it for a while. Anyway, I will send some explaination about how I've
stored the tiles in memory.

Attachment: PCMSD20.BIN
Description: Binary data

Ciao,
 P.