This is a more complex question than just "what is your favorite video game," or "what games do you consider works of art?"

If I'm putting a game in a museum, it's because there's something about it that warrants preservation on a greater level than other games. To that end, my candidates are

• Pong (1972)

The first commercially successful video game.

• Tetris (1985)

Arguably the most influential game of all time

• Rollercoaster Tycoon (1999)

Handcrafted in assembly, serves as a lesson both in optimization and harnessing the players' penchant for finding intrinsic value in simplistic game mechanics

Edit: I just realized this comment looks like an infernal machine wrote it. I want to make it clear that I'm a human, with skin and blood and stuff