I've said it before and I'll say it again: Rayman for the PS1
On the surface it looks like just another colorful 2D mascot platformer. Underneath it's surface however is one of the most grueling and maddeningly difficult games I've ever played.
The game doesn't start off all that bad, but then the difficulty starts to ramp up very quickly. Especially when you reach Bongo Hills. You have a ton of pin point precision platforming which instantly kills you if you fuck up. And some of the most annoying enemies ever to grace a platformer that like to drain your precious health. It's a real drain on both your lives and continues. The latter of which you cannot get more of, and you need them in order to get past all of the really hard levels late in the game
I made the mistake of using up all my continues in Moskito's Nest, which is very early in the game. As a result, I could not get past Bongo Hills which is a very long and very annoying level to get through. I had to restart the entire game and make it so that if I ever lost all my lives on an early level, I would instead reload my last save and start over from there rather than wasting a continue.
This wouldn't be so bad if the game didn't force you to find EVERY SINGLE GODDAMNED CAGE in the game just so you have the privalge to go to the last level. A lot of these cages are ridiculously hard to find, some of which requiring you to jump in very specific points in order for either them to appear, or the platforms you need to reach them. One time the game also spawned a cage right behind me right before I touched the goal post in the level. Unless you had a guide go tell you this ahead of time, there was no way anyone could have anticipated that. And chances are, you'll miss the cage, and you'll have to go through the whole fucking level over again just to get to that one cage.
Speaking of going through levels again, there are also certain cages you can't get to without having certain abilities. So you'll have to revisit and go through entire levels over again just because Betilla decided: "Oh hey! I think now's a good time to teach you how to run!

" two or three levels after the one you needed it in.
I got as far as Skop's Cave before I decided to throw in the towel. Later on through, my brother used a cheat to unlock the final level and get 99 lives. He had me face the final boss, who wasn't too difficult thankfully.
Of course since we used cheats, I didn't really count it as a win. So I still consider the game unbeaten to this day. And frankly, I have no desire to try to beat it anymore. So fuck you Rayman, there's a difference between challenging and nigh impossible, and you are the latter.
I loved Rayman 3 and Origins though oddly.