It's a fun game ruined by ridiculously predatory monetization. Only way to get good weapons is to gacha. To improve the stars on the weapons you need to sacrifice several more weapons to it. It's the same for skills. Except to upgrade skills you need another skill of the same rarity to upgrade it so increase level cap. So yeah you might have gotten a sweet skill but once you hit level 10 and you don't have a skill of that rarity and type tough luck.