• Pong
• Tetris
• The Legend of Zelda
• Super Mario Brothers

But as i hope you can see, these are in their most pure form

• Pong = hit ball back & forth
• Tetris = Drop blocks clear rows
• Zelda = run around solve puzzles
• Mario = run from side to side & jump

But then i asked myself; If i asked 20 random people in the street, what is the last level / dungeon like in those games. would i likely get an answer for a Mario game or Legend of Zelda. The answer would be most likely be NO.
Now this may be where results may vary but threw out my life I've know people who adamently hate video games, this is based on the Outside media's view of games. But I've asked many of them if they have ever played Tetris and many have and they liked it.
using those peoples views and some of my own reason i have come to believe that Tetris is the greatest game of all time.