Horrible controls and lack of instructions really keep this from being a great game.
I think the horrible controls really keep this game from getting to its potential greatness. They just don't FEEL NATURAL. ..... let's see, you have to hold down RB and move your right stick!! Excuse me??? The people who came up with these controls are either masochistic or don't understand good control mechanisms.
The lack of thorough documentation means you have to figure their stupid little mini-games out for yourself. When I first started playing I came across my first decryption mini-game. OK, so B is highlighted. So I press "B". Immediately I get "Failed to decrypt"..... ok.... well, I'm only guessing what to do because it doesn't say in the documentation what I'm supposed to do, how fast to press the buttons, etc. I then reload and keep trying 3 more times, failing each time.
I have visited a few planets and the control mechanisms of the Mako could have done better. It just doesn't control fun nor intuitively. They should have looked at how Halo 3 did their vehicle control mechanisms.
Lastly, I think this game could have used more and varied graphics. I walked around Citadel everywhere. It almost all looks the same. I got confused a few times because many places reuse the same graphics. The graphics could have been better, in my opinion, and they should have turned off the film effect off my default. It looks better that way.