Basically, the game is sort of a "maze", sort of a "puzzle", and occasionally, a shooter. You run around all the levels, performing acrobatic feats such as climbs, jumps, and even trapeze/pole jumps. You have to choose between several paths, and sometimes, locate even more paths by moving some blocks around, and remember when to backtrack. You will locate lots of stuff this way. Finally, you will sometimes enter combat against minions of darkness… spiders, bats, zombies, huge "boss" monsters… and so on. You have your trusty twin 45's, sometimes augmented by various special ammo you find, and later, you get to tap Thor's Hammer which shoots a nasty "firewall".
The game is fully 3D, and even has a "free camera mode" for you to look at things that may not be obvious from one view angle. The camera is very well done… Most of the time, it's in 3rd person, following behind Lara, so you can admire her acrobatic moves. It pans from side to side as the terrain turns, and follows her as she jump and climbs up and down cliffs, and so on.