Pathfinder Flip-Tiles: Darklands Perils Exp. - Rules of Play says:

There are dangers in the Darklands that defy reason or imagination! Flip-Tiles: Darklands Perils Expansion is the newest expansion to Flip-Tiles: Darklands Starter Set. With 24 full-color 6 x 6-inch double-sided tiles, each stunningly crafted by cartographer Jason A. Engle, you can spelunk precarious pitfalls, balance atop falling stalagmite bridges, and brave molten chambers. All perfect for the next time the heroes delve deeper into the twisting passages under the earth!