That game is actually a fan-made project based on the show "My Little Pony: Friendship is Magic". It features a limited roster of characters, mainly from the first two seasons, and neither Rainbow Dash nor Fluttershy are included.
However, there are several other fan-made fighting games that you can find online. These games might include Rainbow Dash and Fluttershy, but they are often of lower quality and may not be officially endorsed by Hasbro or the show's creators.
If you're looking for a game featuring the full cast of My Little Pony characters, you might be interested in:
* My Little Pony: Friendship is Magic - The Game: This is a free-to-play browser game with a turn-based combat system. It features a large cast of characters from the show, including Rainbow Dash and Fluttershy.
* My Little Pony: Equestria Girls - Friendship Games: This game is based on the "Equestria Girls" movies and features the human versions of the main characters. It's a rhythm game with a focus on friendship.
* My Little Pony: Magic Princess: This is a mobile game with puzzle elements and a focus on collecting ponies. It features a large cast of characters, including Rainbow Dash and Fluttershy.
These are just a few examples, and there are many other games available for you to explore. I hope this helps!