Yeah idk, I am not skilled enough to say whether the old games were good or not. In general my memories of 8-bit/16-bit stuff are from when I was like 8 years old so 30 year memories ain't accurate. Like when I was a kid I loved TMNT1, Batman NES, Mega Man 4 & California Games lol.
That being said, this new one definitely is just hard af. Someone said that one of the hardcore 2d platformer streamers streamed the whole game yesterday and it took them 12 hours to beat the first run...which is only half the game because it's GnG. And if you no life it, these games are probably like an hour long, but it still took that dude 12 hours. Sure he was playing on the highest difficulty ("Legend") but in terms of accessibility the new one does a slight job imo of making it more accessible. The other difficulty levels add an extra +1 hit or +2 hit to armor and extra checkpoints and slightly fewer enemies in levels, but otherwise the levels are still the same, the bosses don't benefit from extra checkpoints or fewer enemies so even on the easiest difficulty the boss is still the same boss as the highest one except your armor can take 2 extra hits. Also the bosses are long multi-phase bosses. I'm not saying the easier difficulties aren't easier, but with a game where the levels/bosses are as hard as this is, there's really no difficulty that makes it a little easier for old foggies like myself. The double jump in Ultimate was a lot better for accessibility. I'm mostly just bitching because this game was not catered to me like Ultimate was, but that's fine, it's made for a different audience that digs the old games and wants something similar with better visuals and more content.
There is a "Page" difficulty where you are literally invincible, which is really only useful as a way to scout levels and practice them since there's zero challenge or fun in god mode only difficulty. Also Page ends at the end of the first run, so you can't access the second half shadow stages in it.
I'll probably end up beating it because I don't like to lose and will miserably bash my head against a wall for hours and hate myself until I win, but who knows if I'll enjoy it. I've cleared 3 stages so far and I generally liked them, despite frustrations, outside one boss which was tedious and bleh.