Serious Problems.
For one, the game lags terribly. Your character is rarely looking the way he should be.
For two, the game glitchest a lot. Often I'm just trying to get it to work properly.
For three, it's way too easy! I can beat pretty much any boss or enemy by spamming bullets.
For four, all the crap that they teach you about in the beginning is partially useless since you have to unlock nearly every ability in the game other than walking, jumping, and shooting one bullet at a time. Gee, how convenient.
For five, it's far too short. I beat this in twenty or so minutes, which is rather sad.
For all I said, it's still okay, but it could have been a LOT better.