My clues:

15.  The developer of this game actually created another successful series first.  But then the developers and their publisher were bought by two different companies.  That lead this developer to create this game which had the developer's first series as their main competitor.

14.  This fantasy beat'em up lets you choose from 3 different characters.

13.  One way this spiritual successor changed from it's previous game is that it was no longer a PS3 exclusive.

17. XenoSaga?

#20

Total Annihilation (PC)

Change From Last Year: =

My all-time favourite RTS game. Total Annihilation was the first non-Command & Conquer game in the genre I ever played, and I still go back and play the game every few years, and always have a great time. The graphics are naturally dated, and the AI has its issues with pathfinding as was common with RTSs at the time, but the gameplay is still as solid as ever, and the soundtrack is among my absolute favourites of all time. 

This is one of the often forgotten classics in the RTS genre, and one that inspired a lot of other games to follow as well as introduced various different gameplay mechanics to the genre, including build queues.

No, but same general meta-series.

Xenoblade Chronicles?

DKC2 is a special game. It oozes not only charm, but attention to detail, care, and love in every way. Its pre-rendered psuedo-3D style holds up as stunningly beautiful even now 25 years later, it's incredible soundtrack remains among the best ever composed for a game. The controls are the tightest in any game ever made, and its gameplay is incredibly intuitive and addictive. It is the best platformer ever made (2D or 3D), and is easily deserving of its spot among the best games of all time.

TWEWY is an incredibly unique game. Its fantastic upbeat soundtrack, charming character design, modern setting, incredibly layered story and amazing character development are entirely unlike anything else I've ever experienced. I never got to play the original DS release and so couldn't fully appreciate everybody's high praise, but with its Switch release last year, I got the chance to try it out and was blown away. TWEWY is an utter masterpiece that every gamer should play at least once.

#22
Hint 1: Get all of your characters to the other side.
Hint 2: Each round is set in a different time period.
Hint 3: You can also win by just killing all enemies in the level.

#20
Hint 1: It's just like old television.
Hint 2: The first hint was like a cryptic-ish thing.
Hint 3: New York.

#19
Hint 1: Sequel to #20.
Hint 2: Only numbered game in the franchise.
Hint 3: Most of the map is the same as in #19, but there are some new parts.

#18
Hint 1: Both old and new levels.
Hint 2: It's one of the only franchises in which speedrunning is actually fun.

#17
Hint 1: World with altered physics.
Hint 2: Same franchise as #19 and #20.

#16
Hint 1: Easter Island.

No guesses, so sad reveal time.

21- Dynasty Warriors 7         Unguessed

20- Nioh                            Unguessed

19- Spyro the Dragon Year of the Dragon                 Unguessed

Maybe I will write about them later. But for now some hints;

18- Like other games based on ancient China, this game features the Three Kingdoms. However unlike the other games this game is more strategic and has a more fictional story. It has a strong focus on leading units in battle and then using superpowered abilities to level the playing field, especially on higher difficulties.

17- This game has many levels including the standard levels, castle levels, water levels, even a brief flying level. On 2 player mode, you can take turns with the other player doing levels.

16- The introduction to a mashup of 2 famous series not related to each other at all is surprisingly a very good game.

Pokémon Gold & Silver?