This game is better than "4 stars" but less than "5 stars" due to a few game mechanics. However, I felt it was at least a 4.5, so I rounded it up to a 5.
Bullets, as another commenter mentioned, did not shoot in the right direction, though after a bit you can get the hang of it.
I like the idea of escalation. That starting enemies could be one-shotted and then bigger and bigger enemies come. Either faster or takes more shots to destroy. Of course, this was a ten day game jam and I do not expect people to get everything into a game they think of, so for what you got here in that amount of time really just hits the spot.
I think your fog of war is pretty awesome :)
Amazing job!