Thank you for the feedback and screenshot!
I take it "It does not work anymore" means the save file is corrupted.
I would believe it. There's definitely some bugs out there I haven't fixed. The 'Reset Data' Button should let you start a new run if you feel like it. Or maybe you meant something worse?
There's no way to freeze the shop. I didn't get around to it yet. I might make it so you naturally return to the same shop you have before the battle, but you get a free reroll. One less button that way.
Super Auto Pets was a big inspiration, I want to make something that's a bit more in depth. Hopefully there will be a lot more build options in the game in the future.