I'm not having problems with storage space yet, I'm just very cautious to keep my storage at a decent level to avoid my phone becoming slow. 

The wording of the apk being deleted after installation just made me wonder if failed downloads were also deleted. 

Anyways, besides that, the app is awesome! 

I am having such problems. I "finished" an installation, but then it said "trouble with package" or something along those lines. Now my storage has like 3gb filled and I have no idea where the files are as it isnt shown when I do "analyze files"

Edit:

I "fixed" it by restarting the phone entirely. Not sure if it was just showing an incorrect value before or if it needed a reset to clear the data.

Now I just have the problem that android in all its glory decided that restarting my phone means I want all my folders deleted. After restarting AGAIN I finally got the program shortcuts to reappear, but not in folders...