Nice pixel graphics, I know making rotating sprites that look great is very hard to get right but you got them really right. One thing I thought that could be a really cool adaption to this would be different gun types, or more specifically making the turret a spinning flamethrower (maybe on a fuel meter that replenishes slowly?), but I really like the one bullet idea used here as well. Out of the different "you can't control the direction of where your shot lands" games, this is definitely the best implemented version. Having a consistent rotating turret allows the player to predict and know where they want to fire, and the only limitation is their own timing, which they can improve on through repeat playthroughs. Good game design, friend!
We also submitted a short 2-3 minute game for the jam, it would mean a lot if you could try out and give us some feedback on it, if you have the time :)