Yeah, I apologize for not adding proper instructions... I just had to upload it in a hurry as I was traveling out of town. I'll add them later tonight when I get some spare time.
It does ramp up in difficulty by throwing more flower types at you and it becomes a bit faster gradually over time. It still needs some cosmetic work here and there though. Please don't hesitate to give more feedback, though! Thanks!
edit: removed instructions from here and added them to the game's description text.