BTD6 Round 40 sends the first MOAB. It has 200 health on Medium and Hard, or 133 on Easy, and releases four Ceramic Bloons when its shell breaks. A 0-3-0 MOAB Mauler is a useful early answer if you have a Bomb Shooter, but you also need towers to clean up the Ceramics.
When a run fails here, watch which part actually beats you. If the blue shell escapes, you need more MOAB damage. If the shell breaks but you still lose lives, improve your Ceramic cleanup. Those are two different problems.
How to beat BTD6 Round 40
Start with your strongest existing damage towers and look at how much of the map they cover. For BTD6 Round 40, a central position near a bend is often more valuable than one directly beside the exit. The first MOAB needs to spend time inside your effective firing range.
A 0-3-0 Bomb Shooter with MOAB Mauler deals extra damage to MOAB-class bloons. Keep it covering a long stretch of track, with your existing defence ready for the four Ceramics that follow. Pair it with towers that can clean up grouped ordinary bloons. A high-damage Sniper or other sustained single-target tower can help with the shell, but a defence consisting entirely of slow, strong shots can struggle when the contents spill out.
Do not buy a high-tier late-game upgrade just because a guide says it is strong against blimps. What matters on BTD6 Round 40 is the build you can afford before the blimp arrives. You need to pop the shell early enough that your cleanup towers can finish the Ceramics. A modest targeted upgrade can outperform an expensive purchase that you cannot realistically reach by Round 40.
What comes out when the first MOAB pops?
The Round 40 MOAB contains exactly four Ceramic Bloons. Popping the blue shell is only the first step: those Ceramics still have to be destroyed before they reach the end of the track. This explains why a player can see the blimp explode and still lose lives a moment later.
For BTD6 Round 40, keep an area-damage or high-pierce tower near the section where your main anti-MOAB damage usually breaks the shell. If the Ceramics escape in a group, spreading attacks across several targets is more useful than another tower that fires slowly at one bloon.
The exact place where the MOAB bursts will change with your map, upgrades and hero level. If the shell only breaks beside the exit, more damage needs to reach the MOAB earlier. If the shell breaks comfortably but the Ceramics leak, improve cleanup instead. Those are different failures and need different purchases.
Three checks to make before pressing play
First, look at the entry and exit. On a winding beginner map, keep towers covering long stretches or bends so the MOAB receives sustained fire. On split-lane or line-of-sight maps, check that the towers you rely on are covering the correct route.
Second, check targeting. A tower set to First generally prioritises the bloon furthest along the path; a Sniper set to Strong may help it focus a tough target, depending on what else is on screen. Do not blindly copy a target setting without seeing what the tower is shooting during BTD6 Round 40.
Third, leave enough ordinary bloon damage in place. If your anti-MOAB tower breaks the shell, the resulting Ceramics still require cleanup. A defence that only damages the blue shell is unfinished.
Why BTD6 Round 40 defeats good early-game builds
Rounds 24 and 28 are mainly property checks: can you see Camo, and can you damage Lead? Round 40 is a straightforward damage check, followed by four Ceramics that still need to be popped. Ninja Monkeys, Dart Monkeys and support towers can still contribute, but the combined defence must now handle a much tougher target in time.
On easier maps, upgrading a useful existing tower can be enough. On harder maps, short attack windows and multiple entrances raise the bar. CHIMPS also removes selling, so you need to plan purchases rather than rely on moving your defence at the last moment. There is no universal cheap tower order for every difficulty and layout.
BTD6 Round 40 FAQ
Is Round 40 always the first MOAB?
Yes, the standard round has one ordinary MOAB. Alternate Bloons Rounds also has a MOAB on Round 40, but that one is Fortified, so it takes more damage to destroy.
Why did I lose even though the MOAB popped?
The MOAB releases four Ceramic Bloons, and those can leak if your remaining towers cannot finish them. Improve your grouped cleanup rather than treating the popped shell as victory.
What should I prepare for after BTD6 Round 40?
More MOABs arrive, and the first BFB appears on Round 60. As you continue, keep building both blimp damage and a defence against the layers underneath.
Official game information: Bloons TD 6 by Ninja Kiwi.
