Wave 84 Score 30656
Here's a tip: Create a long, winding, narrow gauntlet of a mix of Machine Guns and Cannons plus several (more for higher waves) Flax Guns along the path of the air enemies. Machine Guns clustered around the Flax Guns would help as well. And don't fully upgrade right away, keep building the gauntlet and upgrading once or twice until there's a really long and winding path. It slows the enemies down so you get more hits on them.
