Regarding the player getting stuck bug fixed in this patch:
When I was playing previous versions of Alpha 1.0, occasionally I would become completely frozen in place, even if the blocks I was standing on were removed, when walking over chests or stairs, and the proxy I use to fix skins in the MultiMC launcher would cease working. Nothing except for reloading the world would fix it. In this patch, you can still become frozen for a split second and the skin fix fails as in the previous patch, but you quickly become mobile again without needing to reload the world.