I know you're all Tomb Raider fans here, but if you haven't tried Portal yet, I highly recommend it. It's a little bit like TR in that rather than being a pure puzzle game, action game or platformer, it's more a hybrid of all three genres. But that's pretty much where the similarities end.
In Portal, you play as Chell, the subject in an elaborate laboratory experiment. You're given a special device—a "portal gun"—that can create interconnected openings between flat surfaces. Early on, you learn to use these portals to teleport from one place to another. As the game progresses, portals also become conduits for transporting objects, redirecting weapon fire, etc. You must then make your way through test chambers of increasing complexity, using only the portal device to solve a variety of spatial and physics-based puzzles, avoid hazards, surmount obstacles and generally get from point A to point B…usually via points X, Y and Z. I found it super challenging and lots of fun.
For more info, including system requirements and the free download link, visit steampowered.com/freeportal. For a more detailed overview, check out Wikipedia's Portal page. Be warned, though, the plot summary contains spoilers.