A really challenging Tower Defense Gacha Games. Despite being a TD game I love how the game use creative mechanics and gameplay in their levels. It really fun if you are into challenging TD games since even with just 4 stars Operators you can still pass a hard or boss level it just that it really challenging and even if you use 6 stars Operators it doesn't mean it an auto win it making level more easier. It really depends on how well you build your Operators.
The lore of the games while interesting the story telling can often be very long that in my memories correct that in one of events in past (I forgot which one) the story is so long that it almost as long as a Light Novel.
The musics are really good that the fans are often joking that the devs are actually music studio that make a game.