Level Select:
Do the following moves in order: Draw Lara's pistols, Take one step back. Take one step forward. Duck and Stand. Spin around three times, then jump forward.

Get All Weapons:
Do the following moves in order to get all weapons. Draw Lara's pistols. Take one step back, Take one step forward. Duck and stand. Spin around three times, then jump backwards.

Hint: Lara's museum:
Activate the switch on the back of the diving board in Laura's pool room. Go to the door it opens in her lobby. Pull the lever, and quickly roll. Sprint straight across her lobby and roll into her museum, barely making it in time. The Dagger of Xian among other artifacts are in her museum.

Blow Up Lara:
Do the exact same moves for all weapons (see above) except instead of having your pistols drawn, have a flare drawn.