Nice idea, but then people will be complaining that 5 minutes isn't enough time to properly test a weapon properly, and there's also the problem that the computer opponent level increases quite rapidly, so you may be defeated before you can have multiple uses of the weapon.

I think a better implementation, would be to have a test area within the shop (a try-before-you-buy thing), where you can also set the build of your computer opponent.

Good idea fake, i like it