Simply complete each objective. There are ways to fail each mission, so be sure to carefully read the breifings for every mission. Use YOUR MOUSE to aim and LEFT MOUSE BUTTON to fire. Other controls will be shown whe ready for use.
You will be given objectives prior to entering a mission.
Tomb Raider: Legend on the GBA delivers a solid platforming experience that actually manages to mix in a healthy dose of the gunplay and puzzles that the console versions contained.