The delay is intentional so the debris from the destructible meshes has time to settle. it got ugly if you threw a bunch of stuff one right after another.
The beer can is larger and can hit more than one mesh at a time so there's some advantage to it.
I will change the fail to reloading the same castle. The original intention was to have a "How far can you get?" style game, but I can see that being annoying.
Thanks!