My hint for 39.

Animals take center stage in this as you do incredible tricks and maneuvers in order to save the world.

Tekken 5: Dark Resurrection

Sonic Riders?

40. Kid Icarus: Uprising (2012)

Another new arrival on the list is this revival of an old franchise.  The combination of bullet hell and hack and slash gameplay is a pairing not seen anywhere else and each section was worthy of its own game.  The flying sections included enough challenge to whittle down health for the ground segments unless you were careful enough to avoid danger.  The hidden and difficulty gated areas in the levels containing extra treasure add a lot of variety to playing through the levels.  Ultimately, the best part of this game for me was the difficulty slider.  No matter how much I played I was still able to push the difficulty up and find new challenges.  The portrait piece challenges are generally well thought out and actually provide meaningful new game challenges instead of just forcing you to play more in order to unlock them.

Nope. Don't think they saved the world, but this game is a older game.

No... they saved the world <_>

Star Fox?

39th - Super Mario Bros 3 (NES, 1990)
Introducing the only pure platformer on my list, Super Mario Bros 3 is probably the best example of the genre which has yet to be surpassed. While since then the genre has evolved and gone into several directions (3D platforming, mixed genre platforming, etc.), SMB3 stands as the example that got it right in all the parameters that a platformer should strive to achieve: Fluidity, fun, a lot of variability in gameplay/approaches to the stages, diversity in stages and replayability. 
Combine all those elements together and SMB3 achieved each one to perfection. 
The game also introduced elements that were to become staples in the series, like the Tanooki suit, world map, stage selection, hidden warps, secret stages, different end world bosses (Bowser's sons introduction was made on this game as well, later to become Koopalings after the introduction of Bowser Jr.), and a plethora more minor elements as well. 
It also had a marvelous art style, in which every element looked like it was part of a play (hence the various theories surrounding this game) which flowed perfectly and were fun to look at in every different stage. 

      

Number 38 hint:

It has the Chaos of the four elements but without a Garland unite them.

#39 - Gregory Horror Show (PS2)

The clues were there, I swear!  Since no-one guessed it, I'll just do a little explanation of what this game is and why it's so awesome.

You play as a boy who stumbles across a creepy hotel in the middle of the night.  In order to escape, you have to collect the souls of the 12 other guests, which involves spying on them through keyholes, learning their routines and catching them when their guard is down.  Once you've stolen a guest's soul they'll chase you whenever they see you making the game increasingly more challenging.  Guests include Catherine the Nurse, equipped with a giant syringe to draw your blood; Mummy Papa, a hypochondriac dog with an axe in his head and Neko Zombie, a cat with his eyes, mouth and ears stitched shut.

Honestly, it's the weirdest survival horror game I've ever played.  And it's genuinely terrifying.

Clue for my #38 - Tim Curry, JK Simmons & George Takei ham it up in the live-action cutscenes for this game from a long-established gaming series.