yea http://xboxclips.com/A 3 Legged Goat/17845f66-746c-41e4-9beb-b460b104404c you can fall through the floor on large circular ramps. there are at least two holes on each the normal and mirrored piece. also, blocks titled at an angle have invisible collision bumps when they connect to flat blocks, which creates a bump can interrupt walking or halt trajectories. maybe this is old news by now though. any other broken pieces?
I knew about the circular ramps when I built Blackthorn. Just place a block under the hole and it is fixed.
http://xboxclips.com/Whos+Blaze/191a0e23-0962-4ca2-a574-f1872db170cd There's this somewhat related glitch with vertical inclines.