Bloons TD 6

This achievement is easily completed on the One Two Tree easy map (introduced in the same patch as this achievement). This map can squeeze three/four towers on each block, each block also coming with an added buff. Fill these up in the early game and then fill the added spaces with 0-0-0 Dart Monkeys and one 0-4-0 Dart Monkey. Should be easily achievable by round 50 on easy mode.