Since everybody's been giving their thoughts on the themes, I thought I'd weigh in for the final round. I'm pretty confident in my ability to come up with something I like no matter what the theme is, so the two main questions I ask myself when voting on themes are:

• Could a complete novice to both programming and game jams make something with this theme?
• Do I want to spend the three weeks after Ludum Dare playing dozens of the over 3000 games that will result from this jam?

Here's how I think the themes stack up.

0 - Automation

This theme has some versatility, but it does encourage games that are reliant on AI, which is a bit challenging for beginners (and one of my personal weak spots as a developer). It also encourages genres with more passive gameplay styles, such as tower defense and clickers, which aren't my favorite.

+1 - Break the cycle

This is a good theme because it could apply to either the gameplay or the story. There are lots of different types of cycles, both physical and social, so I think this would result in a good amount of variety.

-1 - Control the environment, not the player

I suspect that this one would also be a challenge for beginners, but that problem alone would only bring it to a 0. The main reason I really don't want this one to win is because I just spent the last two years working on a game that (mostly) fits this theme. I want to do something different!

0 - Each playthrough builds on the last

I have a feeling this one is going to lead to a lot of scope creep, especially for more narrative-driven games, but it has some interesting possibilities.

-1 - Everything grows

Part of me is voting against this because I already did LD34, where one of the two themes was "Growing" (the theme vote was tied, and I incorporated both themes into my entry). The other part of me is voting against this because the addition of "everything" makes design and implementation a lot trickier under the constraints of a game jam.

-1 - It only changes when you aren't looking

This is too mechanically specific; I'm skeptical that there would be enough variety in the entries. I'd expect to see a lot of games with Weeping-Angel-like enemies from this theme.

+1 - Sacrifices must be made

I almost gave this a 0 because the "...must be made" part strikes me as a bit unnecessary, kind of like how a lot of theme suggestions in the slaughter were "It's all about [X]" or "[X] is the key". I wish they just suggested "[X]"! But nonetheless, this is a pretty versatile theme.

-1 - Absorb your enemies

Also too mechanically specific (not all kinds of games have enemies). I'm struggling to come up with an idea that isn't a knockoff of Kirby, Katamari Damacy, or agar.io.

-1 - Darkness is your friend

There are other things that you can do with this theme, but I'd wager that at least half the entries would be stealth games. Not enough variety.

-1 - Don't trust the game

Of all the finalists, this is the one that I am most strongly against. A good designer can make a great game that deceives the player, but most of the games would be nearly guaranteed to be frustrating, unintuitive experiences.

0 - Magic, but at what cost?

Interesting, but it's a bit restrictive with regards to setting- if there's magic, it pretty much has to be a fantasy setting. I'd vote -1 if it was even more specific about setting, but I suppose there is some versatility even within the fantasy genre. If this one wins, I'd encourage participants to think beyond medievalesque settings with elves and orcs and whatnot.

+1 - Making connections

I believe this is the best theme in the finals. There are so many possible interpretations of "connections"! Are you making connections between romantic partners? Electrical components? Clues in a murder mystery? Airline flights? This theme can easily fit into any genre but still gives enough information to provide inspiration.

0 - One item, many uses

I really liked this theme at first, but I have since realized that "many uses" implies "many mechanics"- not the best theme for beginners, and (per my "I'm in" post) the exact opposite of what I want to be doing this Ludum Dare. I still think it would encourage a good amount of variety, so I won't -1 it.

0 - Take one, leave one

I've been going back and forth between 0 and +1 on this one. Is it versatile enough? Maybe... the "one" is vague enough, but it does imply a pretty specific mechanic. That mechanic could be applied to a lot of genres, though... It's certainly not a bad theme.

-1 - Two connected worlds

Like many others have mentioned, this is strikingly close to the LD30 theme (which was simply "Connected Worlds"). I didn't participate in that one, but I'd like to give its 2,538 participants and teams a chance to do something different.

-1 - Evolve

The theme for LD24 was "Evolution". Maybe the statute of limitations has passed for this theme; it was six years ago and had less than half the participants of modern Ludum Dare. However, I participated in LD24, and not only do I not want to repeat a theme I've personally done, but I also remember it being a particularly difficult theme to brainstorm for and to execute. If this one wins, maybe I can at least take solace in the fact that I get a second chance to do this theme after my first attempt turned out so poorly.

...so, what do you all think? If you can make a strong case for any of the ones I've downvoted, or against any of the ones I've upvoted, I'm open to changing my mind.