I found a funny thing, at the puzzle level called "within reason" i used the Usas12 with all upgrades and double shot, and when i shot, a barrel flied over to the firing zone and the shells that pop out from the top of the gun landed under the metal box, and it didnt count as hitting the ground AKA Losing.
W-w-w-what did just happen there? O_O my heart rate really came up by 100 times man, always scroll your screen down before exiting upgrade screen after buying heart rate.