Grr, I failed on level 51 (the final level), with a score of 15619, on The Plains: Swirlishus.

Nice game!

As for strategies, I almost got owned on level 24 due to lack of long-range firepower, so I started building Missile Turrets in the middle of the map, and upgraded 8 of them (out of 12) to levels 3, 4 and 5. Line up Slow Towers along the road as well to separate enemies.

I'm confident that strategy alone got me to the final level, but my fatal mistake was to waste money on two Laser MegaTowers that were effectively useless due to their lack of splash damage and poor range. Perhaps they become significantly awesome if you upgrade them enough, but a large quantity of long-range Missile Turrets will effectively blow everything on the entire level apart.

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