Oooh, y'bastard. This is clearly going to eat into my time. Just about to start 19...

 

Edit: no, that was easy. Starting 20...

Make that 22, and now I have to go out. Fun that, though.

Hoorar, finished it.

 

I wrote down the level passcodes for levels 19 and 22 to 33, if anyone wants them.

How the fuck do you do stage 28?

There's only one way to get on the splitter without touching the button, but I can't figure how to get the damned block facing that way, not without going over the top bridge, but I can't go over the quicksand. :(

Uuuhh, I seem to recall going up and down the stair-like bit a few times to get myself in the right aligment.

Just in case you get too frustrated, #29 is:

Ended up going for a walkthrough - was really annoying, but I had to know how it was done.

Finished the next four with far less effort, and so I've also completed it. (although I'm still frustrated about 28 :()

https://play.google.com/store/apps/details?id=com.soneraltincit.cubox

Check this out