I don't remember if it was a manga/manhwa/manhua, but the main character (MC) is transported to another world. He is overpowered and fights with his fists. Later, a system appears that helps him travel through these worlds that the MC thinks are movies. Every time he changes world/movie, he becomes another character. In the second world he goes to, he is like an elf demon lord of a forest it wasn't in black and white it was a full colored manga.
I Am the King...?
In order to return to his hometown, the Earth, Gao Miao the traverser, journeys through the IP worlds of novels, comics, movies, etc. Experiencing a variety of different lives, getting to know a bunch of beautiful women, and beating up strong enemies.
This is a full colour manhua. I haven't had time to read through much of it yet, but the protagonist, Gao Miao, does seem to travel to various worlds based on different movies, inhabiting different bodies in each one. This includes a scenario where he becomes a dryad wizard in a forest, who apparently aspires to become a demon king.