Also known (confusingly) as 'Roller Splat - Paint Rush'(!), this UWP game underwhelms slightly, in that the basics of a good puzzle are here and yet so much of the game is missing. You're thrown straight into the linear sequence of puzzles (and thankfully it remembers where you got to), but there's no menu, no home screen, no return level selection, and - most irritatingly - no way to pay to get rid of the on-screen ads. 

From the Store description:

Swipe up, down and all around to send your vibrant paintball rolling through the maze as you splash, splat and sploosh color all over the clean white maze. Complete the levels of each puzzle by covering every corridor and corner with beautifully bright paint. It feels so satisfying, who doesn't love a clean coat of fresh paint?

Roller Splat! is the exciting free game you'll want to tell your friends about. Which level can they get to?!

• Unique and fun puzzles levels
• Smooth and satisfying ball-rolling action.
• Fun and relaxing to play
• Free to play
• Bright and colourful
• Loads of vibrant paint colors
• Simple and satisfying
• Beautifully clean and fluid paint physics

Some obligatory screenshots from my testing:

In addition to the ads on-screen, there are occasional full-screen ads between levels. Are all these really necessary? Surely, SURELY, the developer would get more income from a £1/$1 in-app-purchase to zap the ads? What am I missing here?

Anyway, it's a fun little diversion, almost Zen in the way you work out the sequence and then follow it through. There are no time limits, no counters, no penalties for stopping and pondering or getting distracted. So yes, 'fun and relaxing' indeed. It just needs some work from the developers in terms of monetisation and polish!

(Discovered through MyAppFree)