Hi, cool game, I really enjoyed playing it :)
I have just two points: It would be good to implement some speed scaling that increase the difficulty. At the start of the game it is bit too fast and later in the run, it is getting quite easy when you get used to the speed. Now there is no point in killing the slimes, they are kinda hard to kill and you have to slow down, but you do not recive a reward for it so I just jumped over them. I would implent something to force the player to kill them, like a bonus points or just make the killing easy and satisfying so the player would want to kill them.