Do the arena and pit maps load in Garry's Mod for anyone? Some maps load fine for me, but the pit and arena ones cause Garry's Mod to freeze while it's loading.
I gave that a go. As a Zeno Clash map it froze, as a Half-Life 2 map it worked.
It's odd though; some of the Zeno Clash maps, like coast and mainmenu1 load for me, but the pit and arena maps freeze.