Crack the code.

Silently take out 3 VC.

Escape Kowloon.

Rack up a body count of 20 NVA using air support in Hue City.

Sabotage the Soviet space program.

Escape Vorkuta.

Take down Castro with a headshot.

Kill Helios

Kill Hades

Upgrade any weapon to the next level

Kill Poseidon

Complete the Single Player campaign on any difficulty.