Collect every type of mushroom

Collect every type of bird

Catch a Tsuchinoko (mythical serpent)

Kill The End before the boss battle

Collect every type of fruit

Use bees to harass an enemy

Catch a glimpse of Ocelot, who’s seen behind the president when he tries to shake Snake’s hand

Defeat Shagohod

Defeat The Sorrow

Defeat The Fury

Poison a guard

Sneak up on The End and hold him up

Defeat The Pain