After trying the first cube puzzle, my laptop's keyboard locked. My off button, ironically, offline. Eventually it freeze, and the only way to fix my laptop is to drain the power. And on a laptop where you cannot remove the battery, a massive deisgn flaw, it was a pain in the arse.

This has happened twice to me. The only consistency, is Workshop Mapss, with world portals that go on and off.

Steam Support advised I tell the Workshop Map creators. Needless to say I will no lomger play any map with World Portals if I am ever at risk. Ta.