While testing this game I two possible bugs.
Bug 1: Ususally when 3 animals are aligned in a row without me doing anything they disappear and give me points but sometimes there happens nothing. 3 birds in a row? Nothing happens.
Bug 2: Whilst I was playing a block just randomly "disappeared" or "got blocked". It was free, no animal there. And nothing would go in there, they just went around the block and ignored it.

Either way, have a nice day. :)