Survival mode with inventory and crafting. This mode is being currently developed.
Creative mode with infinite blocks at your disposal. This is a by-product of making the actual game and not the actual focus of development. Multiplayer support for N players (Our humble servers cope fairly well with 10, at least.) Awesome dynamic lighting (quite similar to Minecraft) (This is done with no shaders or such.) Almost infinite world (limited to +-31000 blocks in all directions at the moment) (Minecraft Alpha has a height restriction of 128 blocks) Infinite map generator (Does quite good maps already.) Runs natively on Windows and Linux (C++ and Irrlicht. No Java.)