Holy crap I love this. I grew up playing Jetpack Joyride and this instantly brought me back to those days. This is an instant 10/10.
I'd suggest trying to find out how to give this multiplayer support. I can already imagine how much fun playing something like Ringslinger with this would be.
Ah, this took me back to when I played Jetpack Joyride all the time as a kid haha. Simple but done well, it's definitely fun.
I'd suggest adding a few QoL features, however, like being able to turn off the music. As much as I like it, it can get repetitive after a bit. I'd also make the bullets noticeably spread a little further, since they currently seem to shoot in a perfectly straight line.
That aside, its really fun to mess around with. Plus its fun to look at, great work. Welcome aboard the Message Board!