ESCAPE

You fell down a hidden hole, and now you have to go back to the top in time. You don't want to know what happens when you run out of time. You can also visit a shop after every randomly-generated level to save your progress or buy yourself something nice.

Game is available for Windows and Linux (64-bit only, ask in the comments if you want a 32-bit Windows version).

Use WASD to move.
Left Shift to run.
Use the mouse to look around.
Interact and pick up objects with the primary mouse button (usually the left one).