Rochard is more than your average platform puzzler. It's got beautiful 2.5D graphics, meaning that gameplay is strictly east/west, but the background recedes in beautiful 3D depth and give an illusion of greater space. Sort of like Trine, but deeper and prettier.
Rochard also has a good story, told through cutscenes and voiceover.
The main gameplay mechanic is a gravity gun; you manipulate the environment around you with this one device to solve puzzles, clear passages and fight bad guys. There are other twists, too, like gravity manipulation.
Although I admire Rochard, it wasn't for me. I found that some of the puzzles required more timing finesse than I cared to put up with. Still, I give Rochard a thumbs up, because it's a very good entry in the platformer genre. It's made with great attention to detail, sports a low price tag, and there's a free demo so you can try before you buy. All plusses in my book.