I think the reason I never finish stuff is because I don't like doing the grunt work that makes a game engine usable.
I like playing with systems and mechanics to see what kinds of neat stuff I can make. I guess this is why I keep coming back to Minecraft mods. It's so easy to make something cool and not really have to go to the hard work of building a game around it.
So lately I've been tinkering with some of the internals, seeing what I can nudge around to bring the Minecraft world a little more alive and realistic, without going "this is this way because that's how it is in real life, deal." That is, maintaining good gameplay from realism, allowing the real world to inspire new mechanics. For example, I liked Dwarf Fortress' 2D collapse mechanics and was able to extend them to 3D (and had suggested as such on the Bay12 forums years ago on an easy way to handle it): no need to calculate support all the way down to bedrock. Just look for a solid block 1 layer down and no more than X blocks away horizontally (aborting on finding air), because if that block hasn't collapsed, then it must be supported, ergo it can support upwards. Such a system even allows for domed ceilings over larger spaces. It's great.
Anyway, what I did more recently--as in, in the last week--was yearly seasonal changes.
(You can also catch a couple of trees dying: the logs are replaced, the leaves decay on their own, and saplings are replanted automatically)
The snow there was left over from my attempts at forcing things to precipitate the way I needed them to when it got cold (I couldn't just turn snow on, the biome also needed to have a temperature below 0.2). And it didn't melt (because snow doesn't do that unless there's a torch nearby), so I had to inject that
in as well (the one frame that has more snow was due to it having snowed between frames). And while I was at it, I made it accumulate too. Here's 30 minutes of snow followed by 30 minutes of sunlight. Note: its still a cold
biome, so it doesn't melt very quickly
By this time tomorrow I should have enough to create a full year animation looking at three different biomes (desert, savanna, forest) with one frame taken every 10 minutes. 21.3 hours of real time -> 64 Minecraft-days -> one full cycle (default settings). If I'm lucky, it'll capture rain in the desert (there's a 10 Minecraft-day window for it to happen).
God I love programming. <3