Tools to Darwin

"Upgrade towers 20,000 times"

- Official BTD6 description

 is an achievement in BTD6, first added on Version TBA. It is achieved by upgrading towers 20,000 times. Earning this achievement will reward 200 and 2 random Tier 2 Insta-Monkeys.

Strategy
Nothing much to mention to optimize for this strategy other than the fact that purchasing cheaper upgrades is more efficient for simply trying to earn this achievement.

Tips

 * Dart Monkeys have very cheap upgrades. Spamming Triple Shot with Gwendolin is an interesting strategy while still working well on many of the less difficult maps.

Trivia

 * Tools to Darwin is a possible reference to Darwin Tools.