Requires latest flash player so make sure you update. In game tutorial has instructions. Control your avatar with wasd or the arrow keys. Spacebar pauses. You can hold down ctrl when you select to pick the building under the cursor no matter how crowded a tile is. Pressing escape or x clears current selection. Basic strategy is to build lairs which produce creatures to fight back the hordes. Your avatar will die if left alone so make sure you watch his hit points. Keep ranged avatars out of the path of the enemy so they don't get run over!
An interesting blend of Real Time Strategy, Tower Defense, and RPG. Play as the Dungeon Master and send your minions to defeat the heroes!