I remember my friend at the time made an entire Pokémon game in it, with like 30 different stat modifiers and evolution and everything.
The whole engine fit on a single 3 1/4 in floppy disk. It wasn’t really a very good engine because I seem to remember you had to have the engine to run the games, you couldn’t just bundle them, but if you did have the engine there were quite a few fun things to do.