To describe Gas Powered Games' Demigod as a DotA clone is doing a disservice to its target audience. Demigod is DotA for people who think DotA sounds like a division of Homeland Security.
So what is Demigod? Picture a PC RTS where the player controls a single, gigantic hero unit--an RTS/action-RPG hybrid. Each side has an automatically-spawning horde of minor units, with the Demigod's task being to either direct them to a specific location, or impact the battle to the point that your side eventually overtakes the opposing enemy.