Hey Boris. Thanks for the feedback. I did try to implement a blocking mechanic to the transitions but couldn't get it to work. Sounds were added but removed as they were so rubbish I felt it ruined the gameplay and I didn't have time to search for more. The unkillable should have been Bats, Flames, and Skeletons. It sucks it was only Bats. Will have to see what went wrong there.
Thanks again.