There's probably a bigger market for this next game here

#19: These games have a certain 'face'. They all take the player through various locations throughout the games, but undeniably the first game's main place is a jungle, the third is a desert and the fourth is a caribbean island. This second game, it's an icey mountain instead.

See, this is correct of course.

22: Yoshi's Story

18: Not sure but Metroid?

#26 - Metroid Prime 2: Echoes

I will not talk about this one a lot, since the original is higher and is the bigger reason I like MP2 so much (AKA same engine and level design). But anyway, there's nothing I can think about that I dislike from this game. The atmosphere, secrets, story (backstory), light world vs dark world. And when you find Metroids for the first time, it brings me back memories of when I played Zero Mission and was actually scared of those little 2D monsters. Although, I'm not a big fan of the light and dark beams. Mostly because they are limited, yet you find ammo everywhere, so it's kind of dumb. And the warp mechanic at the end of the game is... silly. But still, great game.

#25 - Mario Kart 7

Easily the best Mario Kart this gen. First one with true customization, amazing tracks and soundtrack. Battle mode is actually FUN, and the online, even back in Venezuela, works really well. And I guess that's it?

I will say, I used to go pretty hardcore on time trials in this game. MK7 is (was?) kind of broken, but in the good way (except for a trick in one track that lets you skip like 1 minute of the track). There were tons of possible skips in many different tracks, and it was really fun experimenting around them to find the best possible routes. There are some few games I would ever consider speedrunning, and this one is just short of making the list (it might have been patched. Plus, there's no real "campaign", so it's pretty boring).

Hint #23 - Another spin-off. This one a turn based RPG, but later on the series loses its love...
It takes place in *ahem* a flat world.

Hint #22 - The first real 3D Mario.

#23 Paper Mario

#22 Super Mario 3D Land

#22 is correct.

18 not :p. I doubt many people, outside gaming websites, have talked about Federation Force. Everybody talked about this other spin-off, though.

#24 and #22 was Maximo VS Army Of Zin and Odin Sphere Leifthrasir.

Hints for the next 2:

#19. This game returned to its roots in 2008 with this 9th installment.

#18. A great platformer that's literally out of this world.

Nobody's even tried guessing my #19 yet, so I'll give the hint again and the one for #18 as well here. I'll wait a few hours before putting #19 up on my list:

#19: This whole series is based on a silly crossover idea between two huge companies and their most beloved characters that quite honestly should never have worked, but somehow they managed to pull it off. This is the second PS2 entry in the franchise.

#18: A PS1 JRPG originally released on the Sega Saturn about 2 years earlier. Contains some rather weak voice acting.

For 19 I was thinking in Marvel vs Capcom 2, BUT, MvsC didn't release on PS2, if I'm not wrong, so I don't know... wait: Kingdom Hearts II???

Kingdom Hearts II indeed.