Light is key (+1): Could genuinely be an interesting theme.

Evolve (0): I dislike it but at the same time I realize it can be a good theme.

You start with everything and end with nothing (-1): Too specific of a theme.

Four elements (-1): Unoriginal and too specific.

Decay (+1): Generally a good theme.

Use the enemies to win (-1): Unoriginal.

Duplication (+1): A good theme with a solid set of ideas.

Expanding environment (-1): Unoriginal and too vague.

Safe in the dark (0): Really just a more specific version of Light is key.

Tiny machines (-1): This idea really just refuses to die doesn't it?

3 rules (-1): Forcing a gameplay limitation on the developer is never a good thing.

You can't control the player (-1): This goes in the unoriginality category.

Alchemy and magic (+1): Fairly open ended and I've never made a game with a magic element so it could be interesting.

Four colour palette (-1): This theme wasn't good when it was suggested in every previous LD as Only 3 colors, why should this one be any different?

What you create you must destroy (-1): It's a bit too specific for my taste. This theme forces pretty much any game to have some kind of sandbox element.

One of you is a traitor! (-1): The overwhelming majority of ideas for this requires multiplayer which is unreasonable for most in a 2 day game jam.