I've got a whole bunch of unfinished games on my HD. Here's some of the most substantial ones that I've been working on in the MegaZeux engine.
Cold Winters
You go hunting for resources during fall, then live off your resources inside during the winter. I had difficulties making the concept work in a way that wasn't really boring and repetitive, so I consider it shelved.
Unnamed RPG project
It's got a working equipment system and a working combat and magic system, but I found the combat too simple to really carry a full game. Unless I come up with a great idea for how to handle the combat within the existing framework of the game, it's canned.
One thing I did like about the game was how each playable character had a unique approach to the spell system and various huge advantages and disadvantages that you would have to find a way to play around.
Attacker vs Defender
I wanted to see if it was possible to make a 2 player simultaneous play game in the engine, so this is the result of that. One player defends a row of blocks and can place new destructible blocks to fend off projectiles. The other player tries to shoot through the defenses. Then players switches roles. The player who survived for the longest during his/her defensive turn wins.
It works, but it's not great. Plus I lost a whole bunch of coding and levels for it during a computer change. It's not solid enough that I'd want to put more work into it.
The Master of Riddles
This one is actually 100% complete! It's a pretty simple game... There are 28 riddles in the game and you simply attempt to guess them. That's it. Coding it was easy. The hard part was coming up with 28 riddles, since I didn't want to just find some existing ones on the internet.