The first few levels of 3-Demon (aka Monster Maze), a 1983 game for DOS PCs by John D. Price and Rick Richardson. 3-Demon is commonly regarded as the progenitor of modern FPS, and is certainly one of the earliest first-person perspective action games produced for PC.
Basically "Pac-Man goes 3-D", the player directs an unseen protagonist through a wireframe-rendered maze, gobbling dots for score while avoiding several ghostly pursuers referred to as "ghouls" in the game's readme. Power pills distributed throughout the maze can be eaten to turn the tables on the ghouls for a short while; a mode well communicated via the Scott Joplin's surprisingly not awful PC speaker background music. The final borrowing from Pac-Man is the bonus "fruit" item, which appears periodically in the form of a floating star and can be eaten for bonus points.
Differences to Pac-Man include a lack of "warps" to the opposite side of the map and the fact that the player can elect to end the level early after eating a minimum percentage of dots in the maze. A radar display shows the relative location of the player, ghouls and the floating star bonus item, but does not show the maze walls, dots or power pills. A full map of the level can be viewed on demand, albeit for a minor score penalty. The player can elect to start at any of nine difficulty levels, with separate high score tables maintained for each. An unscored level 0 is also available, useful only for practice.
Links
archive.org/details/msdos_3-Demon_1983
archive.org/details/3-Demon
en.wikipedia.org/wiki/3-Demon
www.mobygames.com/game/dos/3-demon
gamefaqs.gamespot.com/pc/579078-3-demon
www.pixelatedarcade.com/games/3-demon
www.uvlist.net/game-155835-3+Demon
www.igdb.com/games/3-demon