I love the way Etho parkours through that hole in the crypt lava room, and over the fence and off the ledge in level 2 instead of sticking to the obvious path. Not sure if Tango intended for those to be doable but the extra pathing options seem to help a lot.
At least the bit where they can parkour over the fence is definitely intended. Not sure about the lava room hole... but honestly, it probably wouldn't have survived this long if it bothered Tango / was truly unintentional.