Bloons TD 5
90 Achievements
100,000 XP
Fast Track
Complete the Fast Upgrades Special Mission
1,000 XP
4.58%
How to unlock the Fast Track achievement in Bloons TD 5 - Definitive Guide
On this mission there is 5 waves. After each wave, all your towers get upgraded by 1. The goal is to get 3 boats, and upgrade them to tier 3 on the right side upgrades by the end of the 4th wave. If done correctly, you will have 3 boats upgraded to max in the right side upgrades on the last wave.
Here is the video of my play-through
All I used was one engineer and one glue gunner at the entrance. When you have the money, build and upgrade 3 boats. Placement does not really matter, just make sure they are tier 3 on the right side upgrades before the end of round 4. At the start of the last wave, they will be fully upgraded.
On the last wave, wait for all 3 airships to come into the map. Click your left stick to show the special abilities, and hit the X button 3 times to instantly take down the airships.
This is one of the trickier Special Missions. The trick is to purchase cheap upgrades so that the game will purchase the expensive ones for you (once after every round but only for the path with more upgrades or the left one when both are equal). I'd start with a 0/0 Sniper Monkey set to strong. Then add x/0 Glue Gunners to the left and right and have them level up equally. On the third round you want to get a Monkey Ace and upgrade it to 2/0. Then in the fourth round you want to get a Heli Pilot and get it to 3/0. You can also sell the Glue Gunners and get a Spike Factory to reduce leaks. In the final round you should automatically have a 4/x Sniper Monkey, 4/x Monkey Ace and 4/x Heli Pilot which is enough to win the round.
This is a demonstration of how to win this mission without any Monkey Lab upgrades: