One thing I find with many game series is that as more and more things are added the game becomes more and more complex and one of the main attractions of Hanger (in my opinion) is its simplicity, so while I think that lots of these great ideas should be implemented the core mechanics (e.g. just press enter to go to the next level, space and arrow keys to play) should remain similar to how they are now.
As for new features one of the things I would very much like to be able to do is have more customisation over the character, for example the ability to choose zombie head, robot body and alien legs separately.
One main thing I would like to remain the same is the scoring system, I loved being able to go and replay a level to improve my high score.
Thanks for asking our opinions and good luck!