Co-op game like Brothers - A Tale of Two Sons

Hi! I've a 7 years old twins (girl-boy). They like to play coop (together or parents):
Rayman Origins
Battleblock Theatre
Adventures of Shuggy
ibb&obb
Rocket League
Space Farmers (harder)
Castle Crashers

If she wants to play single game:
Superfrog HD
Last Knight
BIT.TRIP Presents... Runner2: Future Legend of Rhythm Alien
Burnout Paradise
Need for Speed

Harder:
Unravel
Castle of Illusion (Mickey Mouse)
DuckTales Remastered
Blade Kitten

I would say Gauntlet, its not that bloody and there is an option to take out all the gore but it is virtually all combat, I just think your kids might be into it.

I believe you can try:

"The Cave".

You have 3 characters and co-op is also supported. It's mainly an adventure with puzzle elements mostly, and less platforming. It does have a story. I was playing it with my sister recently. It's pretty good. It's not exactly an "easy" game though. Some puzzles are pretty hard unfortunately.

Forced is also amazing for co-op as well as crimsonland, but you wouldn't exactly call these "kid-friendly". Perhaps after some years. xD

Portal 2
Don't Starve Together

Rayman origin and Rayman legend - very fun)
Never alone - beautiful and awesome story
Trine - magic)

And maybe try Ori and the Blind Forest. It's not coop, but very beautiful game

Thanks everyone. For now I installed The Cave and Trine and wishlisted a couple of others. If you have any other recommendations, let me know.

The Cave - unsuccessful

The main problem with The Cave is that it's a bad co-op game. Only one character is the focus. If the other player's character is outside that area of focus, she's helpless. That's unlike Brothers where the brothers can't be separated too much, or LEGO games, where the screen splits if the characters are far apart. It's terribly frustrating to lose control because the other player is elsewhere.

Apart from that, there was no story, at least at far as we got (which wasn't far), it's a puzzle game where there's need to find out what to do, and going back and forth to find that out is annoying due to the above problem and some not so great platforming.