Personally, I wouldn't use zoom at all (and have been told not to use it in my cinematography classes), unless you are going for a 1970s aesthetic where they used zooms a ton. Plus, as I said, it only blows up the pixels in the frame, giving you a distorted image that wont be crystal sharp. If you want to get the same effect, but still retain image quality, and a more cinematic feel, then use a dolly.
When doing a dolly-push-in (where the camera is physically rolled forward), you manipulate your depth of field, giving it a completely different, yet true feeling, of the camera moving through the space, where as just zooming will compress the depth, making the image appear somewhat flat.
An example of a dolly push in is here in my most recent film (starting at 3:15):
http://www.youtube.com/watch?v=ymKX_k6LHIM
And honestly, most people probably won't catch the mic lol. I only caught it because I was constantly scanning the frame. I've done it before too (more than once I'm afraid). Worse for me though, I was doing a film set in the 1860s and dead center between my actors was a plastic Dasani bottle! And only two people have found it thus far in the shot lol. So you just have to keep an eye out for things like that. It's easy to forget when you have a hundred other things running through your mind on set.
One thing I noticed that you did particularly well with is your sound editing. Most films I see, and even some of my early ones, don't "L" cut the sound which allows the audio captured on the previous shot to roll into the next shot before you switch to the audio for that shot (hope that makes sense). The result of not doing that allows you to hear the edit where you sometimes get popping and clicking, and a change in frequency when the shots alternate. I did not hear that with your film, so great job with that! Sound and audio play a huge role in making film seem professional.
Definitely keep on making films, you will grow leaps and bounds with every one!