Overall I thought it was pretty fun but man there's a lot of weird things good and bad and maybe good or bad idk. Sorry if I repeat what others have already said.
Firstly there's a weird sluggish feeling to the attacks. I normally like slower attacks but here it felt off sometimes and I think it's the animations. It's most obvious with the hammer where even if you double tap B, the knight still has a pause between lifting and slamming the hammer. The speed is fine but I think you should look at how Smash Bros and Bloodborne handle the slowness of their charge attacks with a flowing animation where if you just tap your Smash/Heavy attack, the character will simply play a slow attack animation without the charge.
I think the same can be done for the witch's attacks. They're a little slow even without a charge and that's great, but the lack of movement between pressing B and her shooting the spell makes it feel like she's just lagging or doing nothing for that split second if that makes sense.
Also is there a reason the hammer uses a double press for it's basic attack instead of a press and hold like the witch?
I think you run just a little bit too fast for how slow everything else is in the game. Enemies have no time to get you before you zoom past them even if they're already locked on to you. The high walking kinda trivialises the dodge mechanics. I also think you go slightly too far with the knight's roll.
Sometimes it can be hard to aim your attacks. I think it's a combination of the fast movement speed and the fact that both characters lock their aim in place once the attack begins. It makes the timing very strict for turning around to hit an enemy right next to you if you don't want to walk into them like the slimes, so you have to walk away then walk back just to aim your attacks.
I think it'd feel much nicer if during the windup of of your attacks, your character would slow down/stop walking like normal but would maintain the ability to turn around until the attack comes out.
Bugs!
Lock door sometimes doesn't close if you roll through it.
Rolls and teleports don't cancel charge attacks. It's cool and pretty fun but idk if it's intentional. I think you should keep it for the witch.
Teleporting between rooms as witch will have her stay invisible.
KOed witch doesn't revive after reloading.
I got stuck when the Witch got KOed in the locked room, wouldn't teleport between rooms and would stay there even after loading.
Good luck, man. I can't imagine level designing will be easy for this game.