Download Priority: Survive
This real time strategy game is built in an isometric or 2,5D universe, and overall it is a good game to play but at some times it may get too hard, requiring you to replay a mission or so. The action takes place on an alien-based planet where the hostility level is very high.
The computer plays its part very well, maybe too good at some points, but the game is a must-try for every fan of real time strategy games, even if there is no free mode in which you simply start with a base and the objective is to destroy your enemy. You will have to fight your way through a difficult campaign.