Crypt feels like rhythm game with light roguelike touches and not a roguelike that employs rhythm for sure. Given the constraint that's kinda to be expected but theoretically I think with more emphasis on stuff like the spells and less emphasis on autoattacks it could get a bunch more of a roguelike feel. But if the rhythm is still in, I can't guarantee that'd be as fun to play as necrodancer's approach.
I noticed one of the posters hinted that they wanted the rhythm mechanic explored more, and I really agree that it was a missed opportunity for fun factor to not add stuff like the conga boss to the core experience. I actually used to do lots of ballroom dancing, and to me the funnest thing about ballroom dancing is performing an action that costs a certain amount of measures to get some effect, while still maintaining the rhythm. In practical scenarios where you ballroom dance around other random people, this means performing a 1 measure or 2 measure pattern that allows you to turn a corner or navigate away from other dancers you might bump into (this nuance is lost by a Dancing with the Stars showcase).
It's not the execution barrier addition I'm interested in for a game like crypt, it's the beat cost concept that I think would be cool. Imagine that you could buy an item from the shop that says if you skip two beats then press a direction, you deal 3 damage to everything in that direction. Wouldn't that be cool? If this gets introduced later, totally rescinded, but my current impression is that endgame content is going to be based on knowing the enemy patterns and dodging them really well, bullet hell style, while you chip away with tried and true autoattacks you've had since floor 1.
Like, imagine a remade version of crypt where there's a fast low HP enemy 6 cells away from you and a slower high hp enemy 6 cells away from you, and you have a charge staff that can be charged every other phase that does massive damage in an aoe around you, and a high cooldown move that pushes an adjacent enemy away from you. So you move away from both parties, charge the former skill one phase, move away from them , charge, move away from them, charge, then the little fast one is too close, so you fan it away, then you move away again, then charge, then the slower one gets to you first because it wasn't fanned, and you kill it with your fully charged weapon, and then your tiny weapon is plenty enough to beat the annoying guy even if you dont have the fanning cooldown ready to go again yet.