Better than Mario 64, and easily trumps every other game on Wii.
Galaxy avoids every potential pitfall facing it. Obviously two of the biggest threats to its success were gimmicky abuse of the Wii Remote and falling into the colossal shadow of Mario 64. This is a Wii title, you're probably eager to know just how it uses the unique motion sensing abilities of the controllers to enhance the experience.
Firstly, it's a good thing that the controls do actually simply "enhance" the experience. Remote waggling at no point becomes the central focus of the play. From a gamers point of view, it's difficult to see why other developers can't see from the titles Nintendo have put out (excluding Wii Sports, which was intended to demo the abilities of the Remote), that the Japanese console giants only ever intended the motion sensing to be a background feature.
The Remote is used for a few different things. Firstly to execute Mario's primary attack, the spin. A simple shake of the Wii Remote makes Mario execute a short spin attack which damages anything it hits. There is a short period after the attack where Mario is unable to spin again, then you're good to go. The pointer is used to collect star bits which are scattered throughout the levels and can be used to feed strange star creatures called Lumas, causing them to transform into launch pads or even new planets.
Galaxy is a better game than Mario 64 because it knows its limits. At times the 64 classic turned the difficulty up just a tad too high for the genre and audience it was aiming for. Galaxy's missions aren't overly challenging, just enough to keep things interesting, but every inch of every level is an outrageous amount of fun. You could get a heart attack from the sheer adrenaline surge that is Galaxy at its best and die happy.
Another point where Galaxy's Wii peers have fallen short is the visual standards. Galaxy is a rare showcase of the power many lazy, porting developers have impressed upon the gaming public the Wii doesn't possess. No, it's not HD, the stats behind the rainbows no doubt tremble in comparison to a 360/PS3 effort, but the vibrant colors, effects and superb art design are so incredible it hardly matters.
The audio is also everything you would expect from a Mario game and more. For the first time Nintendo have stepped away from MIDI, computer generated music and tested the music with an actual orchestra. Oh dear lord, praise be that they did. The soaring melodies pumping through the speakers are guaranteed to set your heart racing; if not, you're clearly already dead.
Galaxy is a title which strips away the pretentious graphics and technical features prevalent in the modern market and takes gaming back to its roots, delivering an intensely fun experience sure to delight any living human being. Oh, and that Mario 64 shadow? Let's just say the statue of Mario 64 has finally been laid to rest.