Daniel Linssen, aka managore, is a fantastic indie game developer.

I already wrote this sentence, when I covered some of his games in the past: daniel-linssen tag.

In Hop Slide, he was already playing with windows of the player operating system to create a wonderfully clever game.

And he did it again in windowframe!

But not only is the game very inventive, it is also very well crafted and fun to play, but beware: the puzzles are quite difficult!
I had to resort to a walkthtough a couple of times...