Get 35 Thor/hammer vikings max level, max the ship power-ups, and voila, you've beaten the boss without even needing to touch the final 5 islands, even after the +20% boss difficulty increase.
There's no help, options or settings. I forgot what a few units were and what they did, and I couldn't find anywhere to refresh my memory. Every single game has an options/settings button, as it's pretty paramount. And a "help" button is fundamental to a game where there is at least more than 3 things going on. Please do something!
 "Frozen Islands"){kind=icon}
 "Doodle God"){kind=icon}