This is platforming.
You can see how the great moments of the past has been worked into it, and how it appears that games that followed borrowed some elements.
WHAT'S GOOD
The level design - It's fun, and they keep things interesting with visually distinctive worlds, and a variety of jumping, switch, and logic puzzles to work out. Some may say the levels too easy, and some may say too hard. I think a better term to use would be clever. With a good sense of timing being your best weapon, most people should be able to appreciate the challenges the game throws at them.
The method of variety - The controls are very simple you can jump and have one attack. This makes the game more accessible to a larger audience. They way they keep the variety is by changing up the way you use the enemies in the game. Some you can throw or will let you jump high, some act like helicopters, some act as keys, and some have other characteristics at your disposal. This combination makes for a great variety in the jumping and switch puzzles mentioned above.
The Boss fights - They're done very well, and although you feel challenged (or at least not like the bosses are complete push-overs), you never feel hopeless.
Those are the highlights, but they're big highlights. It may not sound like much on paper, but in practice it's rock solid game-play that keeps in it's core what has made many games great: keep the concept simple and keep the game-play fun. Like most games that I find really fun, it's hard to put into words what makes them so. They just FEEL fun.
WHAT COULD'VE BEEN BETTER
A victim of it's own design, and the reason I don't like putting a score on games. In the world of platformers, this game does deserve at least a 9. But the world doesn't consist of just platformers, and in my grand scoring scheme it just doesn't have that special something that pushes it into my group of favourite games of all time.
Although the developers consistently did a great job of keeping the game-play interesting, there are a few shallow attempts of mixing things up. For instance, one level had it so that you could only step away from these statues placed throughout the level for a certain period of time before you had either get to the next one or run back to the previous one. This didn't make the game-play more interesting to me, nor did it add a significant challenge; instead it served as nothing more than a nuisance. Luckily these instances are few and far between.
FINAL WORD
If you like platformers, get this game. It's that simple.