I think I might like Rob, The Dog! And Not The Rabbit! if it was not for a few points:
- I rage-quit at the 2nd level because I find the difficulty way too frustrating, especially the facts that spikes instakill instead of just hurting and that dying reset the level instead of just putting me back at the start without losing my progression in the level. I don't enjoy unforgiving games, I don't play games for adding pressure in my life, I want to enjoy myself. Is that how you want Rob, The Dog! to be?
- It feels so silent, please just add musics which put us in the mood in levels and intros and sound effects for jumps to make them more lively.
- I use to hold jump in order to jump longer, as I think pretty every gamer used to platformers games does, however in Rob, The Dog! And Definitely Not The Rabbit!, holding the jump makes Rob to jump again as soon as he hits the ground. I don't think that you intended to make it this way so I think the game might need a more accurate jumping instruction to understand that it is supposed to jump only once when the player presses jump only once, even if they hold it, it is not supposed to keep jumping again and again.