Interesting ideas for upgrade pacing. I didn't realize on my first playthrough that I could use V, Q and E. While I didn't actually need any of those to complete the game without hitting a critical failure/upgrade point, it did make the game feel even easier. I wasn't able to get the secondary fire to work.
Interestingly, WASD moved my reticle while I held the button, and reset the reticle after releasing - not sure if this was intended behavior. I also ran into an issue where the game played itself to the end without stopping at each group of enemies; that happened after alt-tabbing during a playthrough.
Some camera slowly bobbing and weaving while stationary, and having a bit of inertia when starting to move or stopping, would make the gameplay feel more natural, I think - rather than GO | STOP, it'd probably feel a bit more like the player was flying.
Neat project, nice job on your submission!