As for a few hours, it's really good. I like the time stop mechanic, but there were some details I would suggest: the ghost movement is really slow and R should be a toggle, just like Q so you hold by pressing R and drop it the same way.
The level design was a bit peculiar. You can probably cheese the whole game with one box, since you can drop it and immediately after that, jump on it. Not sure how much of it is intended. If it's not then you could just make it so there's a delay after unpausing time before you can jump.
On the second level you have another box. However, it's not really visible. You have to jump to see it. For puzzle's sake, you could've lowered the top floor so you can immediately see the box and think: "Huh, this box is over there above! Maybe I can use my time powers to get it!". Otherwise it becomes a guessing game of sorts.
I also got stuck in the level with the indiana jones-esque boulder. I didn't get hit by it, but it pinned me against the wall with the box and I got stuck in the wall. That's a bummer.
Still, good job!