I would say Pong approaches easiest for a game with real time graphics, though.

The difficulty of Pong depends to a large extent on how real you try to make the physics. For a classic-style implementation you flip some state bits to test a different axis depending on movement direction; all angles of travel and reflections are defined as a small LUT. The most complex test needed is the paddle boundaries.

Relying on LUTs and state machines to avoid complex behavior is the cheat that defines a lot of the early arcade games, however tutorials tend not to teach them in this way and just immediately dive into trig functions and AABB tests.