Bloons TD 5

This Special Mission is pretty simple, just remember that you can't have more than five towers at once. A Ninja Monkey and Sniper Monkey are great for the first 30 rounds, you might build some farms to easily annihilate anything in the later rounds with Monkey Aces and/or Super Monkeys.

This is a demonstration of how to win this mission without any Monkey Lab upgrades:

The most relaxing and foolproof way to tackle this mission without using dozens of agents is with six Bloonsday Devices in my opinion. Make sure to place them at the back so they the shortest way to reach the most advanced bloons. You should enable Auto-Start Rounds and play on normal speed, then each 14 seconds activate the ability and once you've done that six times for all devices you can play on fast forward and just activate the ability each time it becomes available again. This way you should constantly have one Bloonsday Device active. You might also add more devices to make this even easier. It might be wise to backup your save file before you attempt this mission so you won't waste any agents on failed attempts.

This is a demonstration of how to win this mission without any Monkey Lab upgrades: