Ryan Amalfitano points out this splendid looking RTS. Impossible Creatures is an RTS game with a unique twist: All of your units are created by you personally. The Creature Creator allows the player to combine two animals from a pretty long list and tailor them to whatever they may need, then take them into the fight against opponents. It has a semi-long campaign and online support, as well as a free expansion pack and a variety of mods developed by the fan base. Overall, Impossible Creatures is a great game and lets the player decide how they want to go about things as well as the added element of creativity.
Download: Impossible Creatures Demo!