Patch 3 (25 March 2016)

added option to lock physics framerate to 60fps (improves gameplay fluency on some machines)
fixed collision issues on 'Bridge', 'Train' and 'Serv' levels
rebaked lighting on certain levels to get rid of green spots
proper saving of challenge progress
small challenges flow bugfixes
fixed crosshair staying on screen after running 'diy.exe'