Engine Programmer

Engine programmers are the ones who use game engines such as unity to do a variety of things such as, create levels, large maps or arenas, or setting up a first person camera.

Graphics Programmer

The graphics programmer is the one who uses 3d modeling programs, like blender, to make characters, weapons, items, etc. Sometimes a graphics designer will use a game engine and help the engine programmer make a map.

Game Programmer

The game programmer is the one who codes the whole game, he is the one that gets all the files from the other programmers and puts them into the game.

Gameplay Engineer

The gameplay engineer is the one that decides how the game will be played, what the objectives are, what the items are, who npc interact with the player and each other, etc. The gameplay engineer does some coding, although most of the time they are just telling the game programmer how to set up the certain objectives and such.

Physics designer

The physics designer is the one that simulates gravity, decides what weapons do how much damage, what armor protects how much, the speed of the player and npc's, etc.