Tom Clancy's Splinter Cell Essentials
Hold Select and press L, R, L, R, L, R at the bonus mission screen. Repeat the code to unlock the next bonus mission. The bonus missions are "Paris-Nice", "Heroin Factory", and "Television Free Indonesia".
All bonus missions
Go to splintercellessentials.com on your PSP's Internet
connection, select "PSP User", and enter A27200203S
as a code.
Splinter Cell Chaos Theory reference
On the mission after the graveyard, get to the
part where you escape from your cell. You will hear two men talking
about what seems to be a football player being traded to another
league. This same conversation can be overheard in Splinter Cell
Chaos Theory, during the first mission in single player mode.
Strategy guides from GameFAQs