So what's going on that is good?
Graphics aren't just decent quality for a flash game, but also have a great theme that is consistent with the game's plot, the music, and the overall game feel. Controls are close to tight, I can't tell if you stop on a dime, seems there is a slight delay but it is so close I shouldn't even bother complaining.
Combat skills okay, pretty generic for most fighter games; but generic isn't always bad. The ability to change planes is somewhat innovative. There is a decent learning curve in the first level. I noticed that you can handle the first three enemies as a blue robot. When the first one comes out it is red, and the other two come out as red and yellow. This is great design because it makes sure you get the picture if you decided to not read the tribopedia. Then the blue one comes out, if you are still blue you'll notice that hitting a robot the same color as you has no affect. I should also mention that the game allows you to learn your controls as well when scaling the first set of stairs. This is important because it makes sure you know how to move and jump before entering a fight.
See, I can easily use this game as a good point on well-executed level design. Although I think the enemy variety needs to be introduced quicker and earlier; I love your design. It is brilliant.
What is bad and what should be going on?
I feel as though the keys are too close to each other. This is a matter of personal preference, but it would be nice to have rebindable keys so I can move change robot keys to 1,2,3 and move the menu key to space, since I'm not using my thumb.
Although you showed how to change the settings in the description you actually didn't mention how to in the game itself. I did read the description first (I always do for that stuff specifically) but you should keep in mind that players should be able to access ALL control information in the game, they shouldn't have to read your description when they want to jump immediately into the game.
Another problem is this: the control map. Although you do well with the learning curve I absolutely hate those things where it shows a map of controls before starting the game. I have a hard time complaining against this because it eliminates constant bitching about what controls to press in game, but it is also extremely overwhelming. As a gamer when a control map pops out I feel like I'm wasting my time memorizing them before playing the game when I just want to play the damn game. On a bright note, the fact that you had a spectacular learning curve that makes sure you know the controls well enough balances this out. So that's a save, but it is still good to look for ways to avoid control maps. Nothing pisses a gamer off more.
Last issue is your innovation. The whole "change color" scheme seems very gimmicky. It is the only innovative idea in the game, but making the whole game revolve around this is ridiculous. It doesn't help scale the challenge, it just becomes tedious.
I am rating this a 3/5, however, I would like to note that I feel the review is far more important than the rating; because it's about constructive criticism, and not stupid stars.
Also, if you could I'd be happy if you responded to my critique, not necessarily arguing my point but to give some developer insight. Although I'm a gamer, I haven't developed anything, so it is always nice to get your perspective. I'm curious to what you were thinking for three years. And for the record, I did have fun and I might finish the game.