A "full" trainer that is only 50KB is suspicious. Legitimate trainers for MGS1 are usually between 300KB and 2MB.

Complete the game after not submitting to Ocelot's torture (Meryl Ending).

: Complete the game twice—once with the Bandana ending and once with the Stealth Camo ending. On your third run, Snake will wear a tuxedo. 🧠 Boss Tactics & Pro Tips Psycho Mantis

Guards and cameras will not detect Snake.