I'm aware of the game, and I have no interest in playing it, but I'm confused by what you mean. Is 'hard' harder than 'DS-hard'? What about 'Nintendo-hard'?
Regardless, I didn't stop playing Dark Souls 3 because it was hard, but because it was easy. I've completed it a few dozen times now. I can beat most people in a one-on-one fight even with a substantial handicap, and I can do reasonably well in a 2v1. I stopped playing because I get so few opponents who aren't either blundering dolts or insufferable tryhards, and I'd hate myself if I became one of the latter.
The Souls games' difficulty is very front-loaded. Once you get to know the game, the difficulty largely disappears. With a bit of guidance, anyone can complete Dark Souls 3. Sure, it involves calling in a lot of help, but that's just part of the game and just as valid as soloing the thing. It remains interesting because of the variety of self-imposed challenges you can take on, but those only start getting Nintendo Hard with 'complete the entire game without dying'.
Dead Cells is the opposite. It's a challenging game, but it doesn't take long for you to unlock enough items and upgrades that you can mow down all the enemies with ease. With a bit of luck, you stand a pretty good chance at completing the game after a dozen hours... the
first time around. Then, well, spoilers incoming:
...it unlocks the next difficulty level. There, even with a good grasp of the weapons' and enemies' moves, it's gonna get hard. You'll have to give it everything you've got if you want to beat the game again. Then comes the third difficulty level, and ooh boy, you're in for a world of hurt. Any damage you take is going to put you on the back foot for the rest of the game. You basically need to be able to flawlessly kill bosses. If you're willing to theorycraft the optimal route through the game and the best builds to use, and practice for a few hundred hours, and get extraordinarily lucky, you can beat the game again. Then comes difficulty level number four, which is the developers' way of saying "okay, seriously, give up, stop playing now."
TL;DR: Dead Cells is harder than Dark Souls, in many ways. It's kind of a lazy way of making a difficult game, though, and I prefer games that don't "cheat": no leveling up, no upgrades, no unlocks, no difficulty levels. There are only a few action games that I consider properly hard here:
Teleglitch, a top-down roguelike shooter with a grungy sci-fi aesthetic. A masterpiece of creating tension, an oppressive mood, and even terror, with just a bunch of chunky pixels and bite-sized, punchy sound effects.
Thumper, a 'rhythm violence' game where you speed along a track reacting to obstacles to the beat. It's impossible to do it justice with text, and even
the trailer is inadequate. If you
watch a level being played you can get maybe halfway there, but to truly appreciate it, you must play it.
Receiver, a small game from an FPS jam where you shoot turrets and drones with a handgun, except the handgun is fully simulated. Have fun trying to reload when you can't remember what to press to eject the magazine, which of your other magazines still has bullets in it, and whether you've chambered a round or not.
Devil Daggers, you're on a giant stone platform floating in an endless void and an infinite number of nightmarish hellbeasts are coming to kill you.
Shoot them all and try not to die.There are surely others that qualify but these are, in my opinion, the best ones. I could write another whole post about puzzle games but I'll save that for another time.
