For reference sake, here's a list I found of the best selling video games of all time.
Here's the link
1. "Super Mario Bros." for NES: 40 Million Units
2. "Tetris" for Gameboy: 33 Million Units
3. "Super Mario Bros. 3" for NES: 18 Million Units
4. "Super Mario World" for SNES: 17 Million Units
5. "Super Mario Land" for Gameboy: 14 Million Units
6. "Super Mario 64" for N64: 11 Million Units
7. "The Sims" for PC: 10 Million Units
8. "Super Mario Bros. 2" for NES: 10 Million Units
9. "Grand Theft Auto: Vice City" for PS2: 8.5 Million Units
10. "Harry Potter and the Sorcerer's Stone" for PSX: 8 Million Units
11. "GoldenEye" for N64: 8 Million Units
12. "Donkey Kong Country" for SNES: 8 Million Units
13. "Super Mario Kart" for SNES: 8 Million Units
14. "Pokemon Red/Blue" for Gameboy: 8 Million Units
15. "Half-Life" for PC: 8 Million Units
16. "Tomb Raider II" for PSX: 8 Million Units
17. "Final Fantasy VII" for PSX: 7.8 Million Units
18. "Myst" for PC: 7 Million Units
19. "Gran Turismo 3" for PS2: 7 Million Units
20. "Dragon Warrior VII" for PS2: 6 Million Units
Those figures might be out of date because I've come across figures of 8 million and 11 million respectively for GTA 3 and Vice City. And some of the above games may have very high figures because they came bundled with machines, like Super Mario Bros for the NES. I don't think it means that 40 million people went out and bought copies.
KM.