Come take a trip with me down memory lane:

CD-MAN (DOS, 1989)

I used to play this as a kid in the early 90s. Before that I had only seen Pac-Man on the Atari 2600, which was a rather lousy version of this classic.

Here you had to collect keys to unlock parts of the map. Also, no ghosts, but spiders instead. CD-MAN still looks like Pac-Man tho 😆