Very cool idea! There is also a ton of content in it, amazing for that timeframe. A bit overwhelming in the beginning, maybe a slow buildup would be good - like starting with one mech to learn the basic controls, some level properties (like walls or water) and the basic concept of what fires when. Then introduce another mech to really start the game (and finally the third one). I appreciated the existing tutorial, but i can't manage to remember most of it when playing the game, since it is positively stressful.
Great job :D