I also do this for myself to think properly about the themes.
One Bullet (-1): Bit specific. A bullet has a very specific purpose, so I think it limits creativity (which might help some of you). However it would even disallow the excellent Titan Souls which uses a single arrow (LD: You only get one), a game like Samurai Gunn would still work, but both such games follow a similar concept. I might scare away people who want to make something less standard (but it's getting there) like a visual novel, but I can also see it work, I remember a friend of mine owning a bullet that killed his grandpa's friend during WW2, so storytime.
One Minute (0): Specific, yet abstract. One minute could be a single unit of time in which stuff has to be done (like McPixel, LD: 10 seconds). But it could also be something you would say when you need a moment before you can help someone ("a minute, please", or "min" as we use in chat). In general I think time restrictions are about as restricting as last theme, where most of us used 2 genres - a theme I was sceptical about at first - but turned out very interesting.
Dying Planet (-1): This is a specific theme that leaves a lot of options open. A planet is a lifeless object, so you are open to interpret Dying as you see fit. This theme does force you into using planets in some way, as an object flying around a star or the object that provides you with shelter, resources. But visually presenting this spherical object in a way will be pretty much a requirement for high scores. LDs A Small World and Tiny World have some variations on this already.
Ancient World (+1): Ancient things are shrouded in mystery. As a result you can come up with a lot of story and mechanical ideas. It's a bit close to the recent Ancient Technology theme, yet I feel this opens up a lot of new things to explore in comparison.
Two Points of View (+1): A decent theme that opens up a lot of story and mechanical opportunities. I think it could be a bit close to my previous entry (The Imaginary Room, LD: Combine Two Incompatible Genres), which I personally wouldn't like. For the good of LD though, I think it will spawn a lot of interesting concepts with a lot of enjoyable entries.
Fragile (0): What is fragile. A child? Porcelain? A balance? You can do a lot of things with this. However the ones that are most powerful in meaning, have the least amount of freedom. Porcelain has a very powerful meaning, but will force you to use porcelain. A balance opens up a lot of mechanical opportunities, but it harder to relate to the Fragile word.
The challenge would be finding something that is powerful in both meaning and mechanics.
It’s Spreading (+1): Spreading can be represented in many ways. This allows for a wide variety of visual representations and mechanics. I'm not a fan of the "It's" part, but I think it will be easily forgotten, so it should be fine.
Inconvenient Superpowers (-1): Inconvenient implies bad and annoying. I don't like bad or annoying games. (Although this seems to be a trend.) Let's (finally) forget about this and move on. That being said, Super Crate Box comes to mind seeing this theme, however I can't really see beyond that idea for something more creative that isn't annoying or bad.
Start with nothing (-1): Nothing? Probably not nothing, because truly nothing gives you nothing. Semantics aside, I don't like seeing a lot of Minecraft of Doodle God clones. I do think there is some potential in this, but I don't think many will realise it (including me).
Running out of Space (0): Space? SPACE?!? SPAAAAAACE!?!? Even portal robots know we need space. Limiting it can be a good creative limitation though. I do fear for people all going with the same concepts, such as building on a 10x10 grid or a growing population not fitting a planet or random variations i.e. using cookies and mouths. But there is definitely some room for really creative ideas. Might be a bit close to Running out of Power.
Nothing is explained (0): Isn't this the basis of any good tutorial? At least that's a basis. Exploration of a unknown world can be exciting. It's a bit open though, and could lead to pretty much any game. But I think when some thought has been put into it a few interesting concepts will spawn.
If you don’t see it, it doesn’t exist (+1): A very versatile theme, yet quite limiting. I mean this in a way that you can interpret it in many ways, and each way would provide a limitation good enough to make something compact. The more obvious one is a mechanical one where you despawn anything not in line of sight of the player. But when we look a tiny bit further we find philosophical concepts that contemplate existence and the ego. Then in a more cute sense we have kids that play hide and seek think they are hidden if they can't see you. This theme should contain something for everyone to explore. I'd give a +2.
Colour as a Gameplay feature (-1): I hate it when people explain what to do with their themes (like last time). In my design philosophy colour is always a gameplay feature, in pretty much every game I make. Just make it a broader "Colour" so we can explore non-gameplay stuff and I'd give you a 0, but like this its a -2.
One Enemy Only (-1): Maybe I don't want enemies in my games. Maybe I cheat and use a big tree with it's roots as enemies. This theme needs more thought to be useful. That being said I'm a sucker for a good boss fight.
Build a Dungeon (-1): I don't see a lot of variety here. Maybe the way you make your dungeon, but Dungeon Keeper has explored a lot of those already. Also a lot of people don't like dungeons as it implies fantasy, which - contrary to popular belief - isn't generally liked.
Control two things at once: (0) I see a lot of options, but mostly mechanic wise. I do think we will see quite some variations on it though, I could list 5 just right now, without pause and real thinking (each button moves 2 objects, multitasking sim, mirrored movement, every action has an equal and opposite reaction, every ability does 2 distinct things simultaneously), so it's not a bad theme, just forces you to think about mechanics (which in my opinion most people should do more often).