Sapper is an achievement in BTD6. It can be achieved by popping 5,000,000 Fortified Bloons (including Fortified MOAB-class). Using defortifying towers such as Shattering Shells will void contribution to that achievement. Earning this achievement will reward 500 and 1 Monkey Knowledge Point.
This achievement is arguably the hardest to achieve in BTD6 because there are very few Fortified Bloons in regular games. Grinding Freeplay Mode rounds past 100 is usually a requirement to obtain this achievement.
- Due to the nature of the achievement, popping five million Fortified Bloons can only be easily achieved by the use of later freeplay rounds. See BTD 6 Freeplay Mode/Strategies for strategies to obtain high freeplay rounds to pop Fortified Bloons.
- Playing on Alternate Bloons Rounds gives more Fortifed Bloons than a regular game, although it is only a slight increase.
- As a Fortifed B.A.D. has 192 Fortified Bloons, a total of 26,042 Fortified B.A.D.s has to be popped to obtain the achievement.