Such a good polished game! Congratulations on making on such a short period of time a very well crafted entry! The bullet mechanic was cool and the different enemies made an interesting experience. The checkpoints are a great addition and makes the player feel progress during the playthrough.
I can't think of any bad things other than maybe the way the bullet moves can be hard to catch at first. Overall, a very solid game, you should feel very proud, hope you had fun participating!