Pick Greed Island For This One.
- Start The Game And Run One Direction, Then The Other.
- Grab The Coin Chests Strewn Around The Map To Get Started.
- While You Look For Those Chests, Try To Count The Number Of Tower Placements On The Map (Large Rocks)
20 Tower Spots Are Not Guaranteed For Any Map, But Greed Island Has Enough Space That You Should Not Have To Reroll Your Map Too Many Times To Find A Good One.
- Mine Had 22 Tower Spots, 12 On The Left On The Camp, 10 On The Right, Not Including The Two At Base.
Achievement Pops When You Tell Your Builders To Build The Last One, Actually Finishing The Last Upgrade Is Not Required.
Good Luck!