95% original recordings is amazing, really good initiative there.. and I can totally appreciate your situation. A friend and I just cut/mixed a student piece from a final picture that came in 3 days before the stems were due, and even though we knew we'd be able to go back in after the first screening to clean it up for festival submissions etc., it's extremely stressful to have to pick and choose your moments to cover.
So take my amateur notes with a grain of salt and understand that I respect how rushed you were:
The big one: there are many spots that just seem conspicuously not covered with sound - not eerie silence, just "there's no sound there" silence. In your situation, I would've probably relied more heavily on the camera audio to help that. A good dial edit would add a layer of reality to this piece that you wouldn't have time to artistically recreate. However shitty it was, I would make more of an effort to play up the camera PFX, Foley, etc. More roomy movement from the actor, some shuffling around, some actual shower in the bathroom, etc. At least until shit starts getting wacko.. at that point on I think what you did with the droning music works well.
Main priority of the piece should've been the sound design, and that you did all stuff from scratch shows it. I dig the title whoosh but would maybe pitch it or do a variation for the logo out. The 'rrrree!'s are nice, but again, some variation would be good.. the main culprit here is the silent dream sequence! It strikes me as the moment the story goes crazy and it's dead quiet. Even some verbed out breaths, weird drones, whispers, IR'd winds, something to tell us that we're in otherworldly flashback land would be better than nothing. That stuck out for me.
Another thing you could do, since we don't hear enough of this guy's voice to really worry about matching, is go into your bathroom or whatever and just done some quick breath revoicing, so we are more with him in those routine moments before things go nuts. Doing it in there would save you the time of needing to match/mix it too heavily and your Zoom would probably come pretty close to the camera audio tone with enough distance.
The Foley is good, especially the stuff in the closet. Some footsteps got covered, like the carpet ones, but then coverage for them falls off later!
Final note is that I would watch the room tone/reverb tail cutoffs that happen here and there.. 2:16, 3:39, 6:00. Gotta smooth those guys. If I can hear them on my crappy $20 ATH headphones, they will definitely jump out on a festival playback system.
I will say that the TV futz and room perspective - especially as he comes back in around 4:32 - is badass. Really great job on that, better than I could do.
So yeah man. Sorry if that was a lot of notes, just trying to be thorough..
Quick fixes I would shoot for are just more verb (it's a horror film, no shame in drowning it a bit), more sound design coverage, more camera audio if you don't have time to cut and mix BGs/Foley for the piece.
Hope that helps a bit!