I suppose I should explain the flaws that brought Rayman 1 down for me.
I don't have a problem with the game being hard, I play plenty of hard games, and I often push myself to do better in anything in life if I feel it's worth it.
But the problem with Rayman 1 is that it's UNFAIRLY hard, a lot of the difficulty comes from unclear hit boxes, foreground that looks like background (meaning I've often jumped into walls thinking a jutting out rock was a platform hanging out of some background wall, only to discover that the whole wall is in the foreground), lots of traps that off-screen you (particularly in vertical segments. I hate how the camera in this game does not follow you upwards until Rayman is touching the VERY top of the screen, meaning I often graze off of spike balls and what not that I can't even see, during a tight, upward platforming segment), odd jump physics (Rayman's jump feels ever so slightly momentum-based and Megaman-tight at the same time, which creates a lot of moments where it's awkward to maneuver in the air).
I also greatly dislike how Rayman doesn't have his signature powers from the beginning. It's like if when you booted up Sonic 1, Sonic couldn't actually run fast or curl into a ball until you cleared Green Hill Zone. It's not too bad in the case of the telescopic fist, but the Hair-Helicopter should of been available much sooner. Because when I was playing the first few levels, I didn't see why this game was considered so great at all (other than the graphics and music). All Rayman could do was walk (not even run) and jump. And climb poles. And while he can crawl, it's of no real use early on. Because of this, the first few levels are extremely basic and boring, and there is absolutely nothing about the games mechanics to draw a player in. It's more basic than a fair few 8-bit platformers in the beginning.
I honestly think this game would be a lot better if Rayman had all of his powers from the get go. It's a linear, level-to-level platformer, so holding the powers back from us makes no sense. Metroid games hold back game changing powers from you because they are open-ended and explore-able, meaning the power-ups are a nice reward for exploring such open maps. In Rayman 1, I don't feel rewarded when I get a power-up, I just question why I didn't have such a significant ability from the beginning, especially since the decision to hold them back from me meant that the first few levels HAVE to be basic and boring to compensate for my basic and almost non-existent move set. The level design in Rayman 1 is linear, and very focused on challenging your move set, so it's a bad design choice to assume I'd feel rewarded when given a new power-up.
I could probably go on a bit more, but this is the gist of it. Don't get me wrong, I still like this game. It's fun when you have all of the powers, and the otherwise terrible design choices such as the bad vertical camera and the confusing hit boxes are much easier to deal with when I have the powers to help me. But the powers should of been available from the get go. And those terrible design choices shouldn't be there. Both things really broke my immersion, and decreased the overall fun factor for me.