Unlock all other trophies.
Upgrade your health to the maximum.
That's all there is.
Collect your first weapon.
Defeat 50 enemies.
Defeat 100 enemies.
Defeat 200 enemies.
Upgrade your ammo to the maximum.
Collect all weapons.
Collect all tools.
A fateful encounter on a bridge.
A fateful encounter from above.
A fateful encounter with the unknown.
A fateful encounter from below.
What else is there to do?