To me at least.
On the PlayStation (or PS One if you are up to date with Sony's trademarks) there was this beautifully simple yet mind-bending puzzle game called Kula World. It never received a sequel. So initially, I was kind of offended to find 'some idiot copying Kula World,' under the guise of Puzzle Dimension.
A quick Google search later and all was well in the world. Apparently one of the original people involved with Kula World went on to create Puzzle Dimension, which then instantly makes it awesome instead of offensive! And while it's not an official sequel, I'll treat it as such.
Especially as the game is so delightfully similar: collect key items (sunflowers it seems) to open the exit and leave each level. There are some changes though. The two main ones are in controls and level design.
The controls are different in that the camera is static and you need to change it manually. In Kula World the camera would be linked to your direction of movement. While this gives you a better overview of the levels, it does make controls more difficult coming from the PS game. Using AWSD to control the camera and the arrow keys to control the ball is slightly odd.
Secondly, level design is moving away from the 3D cube approach. Gravity will still shift as you roll onto diagonal surfaces, but Kula World 'cornering' is gone. Which is understandable as while it was a brilliant mechanic, you really needed to wrap your head around it at first.
Apart from that the levels seem to ramp up in difficulty rather quickly, but have a better sense of teaching you about the various changes in the environment. Or just go for the short description: brilliant. You can get it from Steam and it lovingly supports SteamPlay. At the time of writing it seems to have 33% discount, so get it while it's cheap!