Mario Galaxy 2 > Mario Galaxy 1
...carry on.
No way in hell.
SMG2 was mediocre for a Mario game at best.
The game removed the hubworld and was plagued with very boring and very linear level design.
The objective of each Galaxy was essentiall get to the end of the level and collect the star. This made the whole game feel like a boring and painful chore. Being forced to collect stars works in Sunshine and 64 because for 1, you have wide open worlds to explore, with the intro serving as a clue as to where to look and what to do. Despite having less worlds, they were much more creative and interesting to explore.
In Galaxy 2 the progression is just PAINFUL. Having to constantly backtrack to collect more stars was a pain in the ass, and it doesn't help that the objectives are all too similar. Now I know the previous Mario games did this, but in previous games, the backtracking wasn't as constant and repetitive. Removing the hub world was the first bad move and it went a long way into making the game feel very streamlined. Galaxy 2, like 3D Land, tries to be a 2D incarnate with 3D Mario mechanics. The entire game just goes halfway on that, and it doesn't work as well as it should.
2D Mario works because the objective is to get to the end and clear the level and then move on to the next, beating the castle. The focus is on tight platforming and mastering Mario to get over pitfalls and well placed enemies. The progression is linear, but there is not backtracking, this keeps a very forward flow with the whole game, which follows suit with the objective of each level: get to the end.
3D Mario's focus is more on exploration and collecting, not to the extent of Banjo or DK64, and Mario still retains his tight platforming controls, but your are thrown into this wide open playground where you are free to do what you want. Yes you have an objective, to find the star, but achieving that can vary from collecting red coins, to stealing it from a bird, to breaking walls, winning races, etc... All of which requiere a sequence of events which you activate as you explore the level. Mario Sunshine's Noki Noki Bay serves as a good example of this. Sure, there is a lot of backtracking to previous levels, but the levels feel different once you go back, because for one, you've unlocked new power ups which allow you to explore previously inaccessible areas in older levels. Not to mention the platforming challenges are still very well structured into the levels, requiring not just a clever and curious mind, but also keen reflexes.
Galaxy 2 fails at achieving BOTH of these as by blending both playstyles, it removes the strengths from each one. Galaxy 1 did it too, but it got away with it because it played more like Sunshine and 64, likewise it was very fresh in exploring neat ideas, likewise, the open levels were not only more memorable, but also had more variety to them. In Galaxy, all non-linear levels were "collect the 5 obviously placed Silver Stars." It also didn't help that Galaxy 2 was literally MORE of the same ****, without bringing anything truly new around, Yoshi and the new powerups were hardly anything necessary. Galaxy 1 was fine and it did not need a sequel. Galaxy 2 really doesn't have anything memorable to it, and the bosses and challenges were all pathetic. The first 3 worlds felt like awful tutorial levels. Hell, even the more fun and challenging levels were over too quickly. I still remember in Galaxy 1, the Manta Surfing Star had me stumped for hours as I tried to master it over and over again. The only time I died that many times in Galaxy 2 was when I would purposely kill myself to farm star bits.
As of now, I've beaten the main story, and began to explore the extra world, but seriously lost all motivation to continue when the "You need 80 stars" roadblock reared its ugly face again.
If I were to rate all of the 3D Mario, they would be as following:
64- 90
Sunshine- 85
Galaxy 1- 75
Galaxy 2- 65
3D Land- 60
Keep in mind that this is a real rating where 5 is average, not the inflated IGN scores where 5 is bad.
Both Galaxies are inferior for having more linear design and making Mario much more clunky to control than in Sunshine and 64.