My friends really hyped this game up, but after playing it with them for about 20~ hours, I just can't get into it.
It was fun at the start, but the gameplay loop just seems extremely samey. Take missions, kill boss, use boss materials to make gear, repeat. I didn't find it rewarding in any way, and there was an armour/weapons set much stronger than the rest without needing many items at all.
There was also this 'tower defense' mode, it sucks.
I think people play this game because the two girls are very cute.