Roofbot: Puzzler On The Roof by Double Coconut LLC $2.99

Roofbot: Puzzler On The Roof is a very highly polished puzzle app game.

The object is to move the robot along the grid to pick up objects and drop them off at their targets, then arrive at the green square. Each square can be traversed just once.  Except for some, which can be traversed twice.

Of course there are wormholes.
Some squares cannot be landed on; instead, they propel Your Bot to the next square

There's a lot to like about Roofbot. The graphics are terrific; if your Bot stays put for a while, he'll juggle or play the guitar.

Most importantly, the levels get pretty tough.  There are 120 levels and I've done 51.

https://itunes.apple.com/us/app/roofbot-puzzler-on-the-roof/id1148435076?mt=8
https://play.google.com/store/apps/details?id=com.doublecoconut.roofbot

Try these other Topology puzzle apps. 
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Flud  - hard!