Angry Birds 2 follows the pattern of many sequels to popular games by once well-meaning studios; Plants versus Zombies 2, the more recent Peggle games and all these iOS sequels of non-mobile games. It takes a cool core idea, adds free to play mechanics and other useless busywork and hopes to bank on some nostalgia here and there. There's also something a bit silly in calling a game "2" when you have made about 30 of them, but that's another story entirely. Angry Birds 2 gets a 2/5, because it's pretty bad.
The core idea of the game is still okay, you shoot birds at structures to destroy them and defeat pigs. Some structures are made out of different materials, so you have to use different birds. The card system they've added is pretty dumb, you use up cards to shoot birds and you might recover some if your combo meter is filled enough, if you run out of cards, you have to restart the level - or pay up some jewels. That's always a bad sign if you can't be sure where the balance really lies; In an experience that's though, but fair, or in a tiring slog that would only be fun after you had spent some currency?
You play the game on a world map where you go from stage to stage - with required loading screens in-between everything, ads, prompts to watch videos to get free stuff, etc - and then you shoot some birds at the pigs, then you go back there. The progression could have been okay if you didn't have to go back to the world map every time and just played the game, level after level, getting new spells, birds and other power-ups. Oh and there is an energy timer because, of course, in our unbalanced physics-based game with a high risk of failure, what you really need are limited tries. You have a limited number of spells as well, so they're not really a mechanic but more of another crutch you could pay for.
Don't play angry birds 2, it's bad. Play the original one instead, if they haven't remade it to add garbage all over it!