It still amazes me how coherent roguelike platformer Spelunky was, despite its dozens of moving parts. Monsters, traps and players interact with each other in so many ways. Next year, Spelunky 2 is adding a bucketload of new elements and systems to its repertoire, as you can see in action in the new trailer below. There’s physics-driven fluids, arrows you can use as footholds, mounts you can gracefully leap off Yoshi-style just above deadly pits and a gun that clones kitties. Oh, and online multiplayer – that seems important.