I mean, I'd be pretty pissed too if I had to work after death...
Unless they put me in the TD department, 'cause that was fun :)
A couple pointers: first, I think it should be more obvious were the souls are coming from and the direction they're going; the story already helps with this: just putting a portal at the end of the path would be good.
Second, maybe an explanation for the different towers would be helpful? I guess they don't really have abilities, other than different range and damage but... I'm not really sure?
Anyway, the game was a good few minutes of fun and it was hard enough that I had to retry the levels a couple of times, but not so hard as to be overly frustrating. Good job!