Are there any missables?

Nope. After you beat the game you can load your save and do whatever you missed.

[PC] Why does my game run like garbage?

If you are on laptop, you need to make sure the game is not running on integrated graphics.

Windows 10 Settings -> Search "Graphics settings" -> Browse -> Select the game exe -> Options -> High Performance -> Save



shop items change as story progresses, so some accessories are missable. These accessories come with 2 blank effect slots, which are optional for ultimate building.