imma look you dead in the face and say that Ultrakill IS hard both in gameplay and controls but after controls are learned gameplay is not as hard
The only people who would have such convulsions are epileptics
Mario: B to jump, Y to run
Pizza Tower: Mario but with some extra Italian flavor
FNF: As simple as you can get with a video game honestly
Ultrakill: D + H + N + Y + W + F + U + C + K to attack
Well there's an explanation for both
Combos
Individual weapons require one key
Then there's switching between weapons and moving
And this applies to both games