Hey! Nice game! For most games I struggle with understanding how to play them - not this one. The mechanic is dead-simple, even for slow-brainers like me :-D And I I even managed to win, yay!
I am so impressed by the fact that this game has been in development for only about a month! It already feels so polished and rewarding.
As for the questions, I can say that using keyboard feels really good and flawless. Also the movement speed from the beginning is well chosen, most games go too slow, but not this one. For the UI, I was a little irritated with the pre-selected "1 Player" Button. Offering such a select state often comes with a "Confirm", but here I had to "confirm" by clicking the selected button again.
As for the content I don't have any valuable feedback, I enjoyed the selection as it is. The only issue I had was visually distincting between collectables and enemies, when things got hairy. So it happened I was running into enemies while I was trying to collect dropped items.
Good job! Keep up the good work!