Why Is FNAF 2 Considered Harder Than the Original Game?

I’ve recently started playing Five Nights at Freddy’s 2, and I noticed that many players say it’s more difficult and stressful than the first FNAF game. The lack of doors, the need to constantly wind the music box, and the different behaviors of each animatronic make it feel overwhelming at times.

For experienced FNAF players, what do you think specifically makes FNAF 2 harder than FNAF 1? Is it the game mechanics, the animatronic AI, or the faster pace overall? I’d love to hear tips or insights from players who’ve managed to beat the later nights.