Downloaded Exp 0.54 (19.02.2015) to check it out, Hoping to have some fun and test the changes i open FRAPS to check my fps while playing since the game does not have its own way to measure this, and played for about 5min with no issues untill everything went full potato on the screen, massive drop of fps, Lara Crofts style of polygones on everything, insides of buildings wont show, textures gone to pixeland andd so on.

The problem solves for a limited period of time ranging from 10sec up to couples minutes if i change the render resolution. Not to mention closing and opening back the game. (Or turning off FRAPS)