I was wondering is using emulators and roms legal?

I read somewhere that emulators themselves are fine, but games have copyrights.

I know this is nitpicking and everyone uses them anyways, but i was curious how the thing is in legal perspective.

Merry christmas!

Why that space ship is not already spawned when i play moon level? All videos what i have watched the space ship is allready in place when player runs to it. And how i can skip the gravity part at Fenton room? And death warp after getting last robot piece did't work, is there something i should know about that. I played on easy.