I watched this video the day you put it up, Marc, but I'll still comment.
While it may not be that hard, as you said it was a medium, I think you also mentioned that you had to memorize where enemies spawned, and where you need to be at certain points in order to get through, and personally, I think THAT is unfair. If a game wants to be challenging, make you die in one hit, make the enemies Overpowered, etc. that's fine, it can do that, a good challenge is always fun, and gives the game more replay value (mostly because you can never beat it....), but making a game require you to memorize spawning points of enemies to get through without dying, THAT is cheap.