I am looking for a really-bad-by-design chess engine, compatible with Arena chess GUI. Not just lowering engine power.. I have tried lowering Stockfish's power, and it didn't suit my needs, so I am looking for a weak one!
You have a whole list at http://www.computerchess.org.uk/ccrl/4040/
If you're looking for a weak engine, I'd suggest:
- Predateur 2.2 64-bit
I know those four engines work and run smoothly, although they're quite weak (which is exactly what you want!). Any Elo 2000 rated human player can trash them easily.
__ My Recommendation __
If your engine can't even beat the lowest Stockfish level, maybe it'd be a better idea to focus on your engine, such as adding easy technqiues like null-move pruning. As an average human player, I can consistently beat the lowest Stockfish level, it plays around 1500-1600 level. Even the engines I mentioned might be too strong for you.
I found it! UFIM works well for my purpose!