Heh.. I don't know where to start.. I suppose the first thing I should say is that the game for me ran smoothly. The problem others are experiencing isn't one I'm having.
Anyway you said this was your first game and I must say for a first, damn good! I actually found you did really good on half the controls and not so great on the other half so I'll start with the good.
As far as movement goes aside from wall collision and such which starts to cause some issues jumping and swapping directions is surprisingly smooth. Even the carpet controls are smooth! That being said when you exit the carpet mode your guy falls straight down allowing no control which I'd consider to be an issue. The other problem I've experienced was that you direct your shots with the movement keys which cause a couple problems making enjoying the game a little more difficult.
The last problem that comes to mind would be bullet speed-movement speed. Lets say the controls were smoother it would be too easy. Because the controls aren't though it's at times incredibly difficult to get out of the way in time
(I say this because I used carpet mode 100% of the time seeing as it was purely better than walking, and I wanted to shot faces at all of the guys which I couldn't pull off while trying to aim, and move. Because of this I let myself fall which was always a bad decision because I fell straight down and got it.)
If I was to suggest a solution I wouldn't just say tamper with the controls and fix it up but generally (This is just what I think) But slower moving bullets are safer as long as you use a lot of them. I've always found games much more enjoyable when a lot was happening on screen but it was all avoidable with a reasonable time to react.
Anyway just my input as I said at first I do think you did a pretty good job on this game. Great voice acting, and the audio track was pretty good. Everything can use improvement so don't let the criticism get to you and hopefully I see more from you in the future!
(Exhausted, sorry if this abomination of a review is hard to read at times.)