Unlimited saves on all platforms. However, PlayStation players should note that this game doesn't allow you to go back to previously played levels unless you have a saved game from that level. There are 70 secrets in the game. A chime sounds when you locate a secret, and the statistics screen keeps a running total. Unfortunately it doesn't tell the number of secrets in each level, so unless you look at the walkthrough, you won't know how you've done until the end of the game.
Secrets consist of ammunition, med-packs and the occasional weapon.
There is no bonus for finding all secrets. There are no bonus levels and so far no expansion packs. However, the London Times has teamed up with Eidos to released a special exclusive level built using the TR4 engine. In this mini-adventure, Lara explores a newly discovered area of Tutankhamun's tomb. See the downloads page for links.