Hey! For your first game, this turned out pretty well! I like the basic gameplay loop and you did a great job implementing a functioning upgrade system. However, the volume of the audio is quite loud, so you might want to turn it down. Also, I think the time period for rewinding upgrades should be longer, given how long it can take someone to have enough coins to purchase the more expensive upgrades. Good job!  

I like how the enemies are emojis, its kinda cool. I wish I could turn the volume down, and adding some juice to shooting wouldve been nice, such as screen shake or recoil. Nice game!