The Global Game Jam page for our game with download link can be found here.
You basically run around picking up people and either throwing them into the volcano to calm it down, or throwing them into other people so they breed and produce more people, who can then be bred again in turn... or thrown into the volcano.
As you're doing this, the volcano spits out fireballs which must be dodged, and which will solidify into new ground tiles which you can also pickup and move around to change the landscape.
The visuals and all core gameplay functionality are almost entirely his work, while I tweaked some balance, made the menu, and did some of the simpler elements such as laying out the tiles for the island, creating the rising water and volcano eruptions, and building the system for the gradually increasing fury of the volcano. I also found and added the sound effects, and added split-screen multiplayer (which is not as impressive as it might sound, since Unreal makes it pretty easy - the biggest challenge for me was getting the game to restart properly from a split-screen game without the camera getting messed up due to the extra player).
Basically he handled most of the work involving more complicated maths and vectors, while I helped out in other areas. You can tell he did the art since the game looks so much more pretty than anything I would normally produce!
We produced a lot of content and systems given the time, but didn't really have any time left over for playtesting or ensuring all the mechanics worked smoothly together. I think we only managed to actually play a multiplayer game together after we had submitted it to the compo! The biggest weakness of the game is probably there in the balance of the different mechanics, which I imagine could be solved fairly easily with a bit more thought and time applied to it. Nonetheless, the basic gameplay is still fun, and I really do think it looks nice.