A lady who witnessed this said there was a puff of smoke and a boom. Because she used the term puff of smoke, I assumed it was a fairly small explosive package.
The half-time Boomer fizzled and had an audience of only one, evidently.
A friend who attended the game said he heard the boom and thought it was thunder, but looked around and there were no clouds.
I think there's little doubt that the guy did intend a spectacular half-time show. Must not have been paying attention in his electrical engineering fusemaking classes.