Thank you! I was able to recover some data from the save file, but unfortunately, I have not been able to reproduce the issue exactly. I am sorry about the bug and I will look into it more when I find some free time! Thank you for letting me know about the issue, I try to fix all issues with the game wherever possible.
Also, after closing error (L R SEL START) and playing again (as i said, it restores data before going to shop), if you go to shop and buy anything again, the same problem will occur.
And another thing: if you buy anything from store, and there's no space for it on your island, game will kinda softlock in "choose place" state. (not freeze, but softlock: you can interact, but can't exit choosing place state)
Btw i entered in storm instead of shop>exit and won! I didn't even repair anything during combat, storm was easier than i excepted)
I'm gonna try higher difficulty.
About the shop soft lock: I will fix the shop to prevent this from happening, perhaps by giving the player extra terrain if there's no space. The "choose place" selection still lets you access the salvage menu, so you can remove blocks with the B button, although I admit that this isn't obvious.
Great job winning! The hard difficulty has a more challenging version of the final boss.