I got 12 cats and I tried all the buttons. Of course none worked. Checking the source I see the fault in line 296: max_cats = level + 5; At level 7 that's

I got 12 cats and I tried all the buttons. Of course none worked. Checking the source I see the fault in line 296: max_cats = level + 5; At level 7 that's a possible maximum of 12. Edit: you've pointed this out in your comment and I somehow missed it.