So the upgrades are permanent, and if you survive the timer the wave will spawn, so instead of killing the first two bosses incase someone was struggling they could survive and collect shells and upgrade there, I had considered putting it at the beginning cause it might have been better but there's kind of my thought process, Thank you for playing my game!! and much appreciate the feedback, by visualize you mean say how much your stats go up? im guessing, if that's the case I didn't about it til my friend played it after I submitted it