I'm not sure how to be honest without being harsh, so here we go:
Samus had no reaction to the Metroid blowing up the tunnel in the "cutscene," yet was still able to scan it without turning around, which makes no sense. Her running animation has no torso movement and, as a result, looks really bad. Double-jumping doesn't require two "X" presses as is stated in the tutorial, but instead requires "X" being held (or at least, that's the only way I could get it to work). The screen randomly fading to black (which sometimes lasts for a few seconds) is... well, I'm not sure what that is. I'm guessing it's the transition effect from the actual Metroid series, but since the player maintains control it doesn't work as well. Then there's the "boss fight" against Bio...droinder? Biodroidner? Either way, having an encounter that requires some luck on the player's part wouldn't be so bad except for the fact that the "Continue" button that appears on the Game Over screen simply takes you back to the main menu. I'll admit it, I never got past the encounter myself, but after watching a few playthroughs online, I don't think I ever will.