Perspective is the way the player see the game. A game can use more then one but one will often be the dominant one.
Top-down
View directly from above with camera looking down. Can be used with parallel or perspective projection.
Alien Breed https://www.youtube.com/watch?v=N-aSztV1QLo
Side-Scrolling
Game world seen from the side. Named after classic games that scrolled to the sides but often possible to move up or down.
Super Mario Bros https://www.youtube.com/watch?v=ia8bhFoqkVE
Perspective
First-person perspective (FPP) - When you see the world from the perspective of the avatar you play. Like from the eyes of the character, driver seat of the car or the flight deck of a plane.
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