Thanks for letting us know it works!
The game is not open source, but the repo might become public at some point. The assembly source is highly obfuscated because I had to do a lot of trickery to squeeze it into less than 4000 bytes. If you are interested in the source dm me at @bag_of_hats on twitter. :-)
Regarding extra features, we will not be updating this project because it was made for a contest, but we are working on an extended version of this game which we have called Rogue64. The new game will add a few extra features. Here is a screenshot of what will be on the zzap64 coverdisk:
