It's probably worth mentioning that it's very possible to crash your browser if you're overzealous with the level creator. Wave time is the amount of time before the ducks fly away. Difficulty is rated from 1-10 and controls the speed of the ducks. Anything over 8 is kind of ridiculous. The bullet and duck counters have a maximum size- you will receive everything you configure but they may not all display if the number of bullets or ducks is too high.