This is some good stuff! I'd also like to see walking sound effects be added to enemies and a variable for jump height.   

You probably also know about the bug of duplicating entities when loading saves.

Yeah, enemy movement sound effects are probably a good idea.  
You can currently jump higher by changing the gravity with a script, but you'll fall down slower too, so I'll consider adding player jump height.  

And no, I'm not aware of a bug that duplicates entities when loading saves.  
1.8 fixed a bug that would cause doors to duplicate when loading, which might have been caused by the same issue.  
But if you're still experiencing a duplication issue in the latest CE version, I'd love to discuss it with you so we can find the cause.