I completely agree with what you said about the powerups. I wanted to add some way to save them for later, but I unfortunately ran into a few issues with UI scaling and camera sizing right before the deadline of the Jam that I had to deal with instead. I also would've liked to make enemies, when they run into you, maybe knock you back and stun you for a short time or something along those lines. I'm sorry about the resolution problem, this is the first time I've actually really gotten to work with WebGL and I don't know how to fix all that stuff yet.
Thank you so much for all the great feedback and for playing!!