UniWar

From the official site:

UniWar is a turn-based strategy game with multiplayer online gameplay for up to eight players as well as a single-player campaign mode. The player's goal in each level is to capture all of his opponent's bases. For each base the player controls, he earns additional credits which can be spent constructing units such as tanks and helicopters.

The game consists of twenty one single-player levels and three armies: Sapians (humans), Titans (machines), and Khralians (aliens). Each army, or race, includes 8 unit types, and each unit type has different degrees of mobility, attack strength, and defense. Special units such as the Sapian Engineer cannot attack or defend but have unique advantages such as the ability to re-program enemy units, effectively converting them to Sapiens unit. Attack is the best form of defence in the game, but in order to succeed at Uniwar players must employ strategies in order to use their limited resources effectively.