This is a pretty neat concept, and it's done well. The art style is simplistic but cohesive, and the paperdoll-style characters bring out a retro, almost DIY charm. Aiming being separate from character movement is a unique touch and the movement sells the Spartan's mass. It's like you took the aiming mechanics of Sierra 7 and coupled them with actual movement mechanics. Really cool touch.
It would be neat to see this concept expanded upon, such as by adding elevation and cover to maps, aggressive enemies that could put up more fight and use that cover, and configurable numbers of allied and enemy AI for more expansive firefight or bot multiplayer-style battles. A game like this could easily run away and become quite the sandbox with the right tools and mechanics, especially if players could tinker with the game on their own.