"It's an action/RPG/RTS hybrid, inspired partly by the popular WarCraft III mod Defense of the Ancients."
(For those who've never tried DotA, it concentrates on two teams trying to destroy each others' bases; though rather than managing all the units or gathering resources as in a regular RTS, players each control a single Hero unit with different powers, leveling up by killing A.I. enemies around the map.)