God I love upgrades. This game is great, also surprizingly challenging! I thought it was gonna be pretty easy but no. My time is 7:49. Really cool game, fits the theme and I had lots of fun playing it, I would give the player a bit more feedback for when they kill and enemy, to make it feel really rewarding killing the enemies, also some feedback for the upgrades, a simple sound effect could enhance both of these experiences. Very solid game!