I'm also playing Hotline Miami 2, and I actually think it's better than the first one. It is definitely harder though, mostly because of larger levels and you'll often be killed by enemies off screen, which can be annoying at times. The difficulty kinda picks up where the first game ended, like the first levels in this one is as hard as the last levels in HM1.
It's like the game expects you to have played and mastered the first one, which I think is great. But on the other hand, I can't even imagine how fustrating this game must be if you haven't played the first one to the point where you're good at it.