Nice idea. I love the robot doctor who comes to repair and improve the weapon.
But after some upgrades, you can just stay in front of the boss and wait to kill him. Maybe enemies should be spawned from elsewhere than just in front of of you.
I did mean to add some horizontal enemies to force you to move more, as I go closer to the crunch I wanted to make sure I gave players a win condition. I really wanted to give him a beam weapon too but chickened out of trying - next time :).
Would have loved to add more interesting baddies with different movement and abilities (like spitters that come from the sides)
I intentionally allowed you to get upgraded enough to camp the boss as I thought if I made it more unwinnable it may give people a more negative experience.
