Very hard to decide, the N64 didn't have a massive library but what it lacked in quantity, it more than made up for in quality. My top 5 would be -
1. LOZ: Ocarina of Time
2. Super Mario 64
3. LOZ: Majora's Mask
4. GoldenEye
5. Diddy Kong Racing
Other superb games N64 games in no particular order -
Conker's Bad Fur Day
Jet Force Gemini
Donkey Kong 64
Paper Mario
Banjo Kazooie
Banjo-Tooie
Perfect Dark
Pilotwings 64
Lylat Wars
Blastcorps
Mario Kart 64
Rayman 2: The Great Escape
Resident Evil 2
Excitebike 64
Mario Golf (hugely underrated!)
Turok: Dinosaur Hunter
Turok 2: Seeds of Evil
1080: TenEighty Snowboarding
Wave Race 64
Mario Tennis
F-Zero X
Quake
Quake 2
Sin and Punishment: Successor of the Earth
International Superstar Soccer 64







