Thank you for your feedback. Glad you enjoyed most of the aspects so much! Firstly, the default controls for keyboard are actually the Arrow keys + Z/X, WASD is an alternative for people who prefer it. You can remap everything as you want.
For the theme - a generic soccer-like type of game is not my style at all. While the setting is sci-fi, the main character wears a soccer-inspired uniform and uses a ball in a vaguely sport-like setting, the rest is up to player interpretation. This is about as much as I was willing to compromise with how specific the jam theme was, the intention was to make it at least worth 3 stars in theme, it's fine if you don't agree.
"Nobody is going to play 10 minutes all over again" is valid criticism for this jam in particular, but in general - this isn't really true and strongly depends on scene/genre. It's actually on a very low end of length spectrum if you take shoot 'em ups, for example. Online leaderboards would be great, wish it were possible.
You cannot die, but some score bonuses are lost if you take hits. There are no threats until the boss fight begins, so having the player die and lose the run only during it would make little sense. I don't think it makes the game more boring or more fun, since the objective is not to survive, but to make precise shots to take down as many enemies as possible for higher multiplier.