Strategy:Sniper Monkey (BTD6)

The Sniper Monkey is a tower that excels at dealing high damage. Its Path 1 upgrades focus on single-target damage, and excel against MOAB-Class Bloons. Its Path 2 upgrades deal solid grouped damage, while its Path 3 upgrades focus on high DPS.

General tips

The Sniper Monkey has global range and can attack Bloons anywhere on the map. This means it shines on maps with little to no line of sight blockers, as well as maps with specific placements that benefit it (such as the stone platforms on Dark Path).

Base

The base (0-0-0) Sniper Monkey's slow attack speed makes it a poor early-game tower in most cases. However, on long maps (such as Resort) it can be useful as a cleanup option for leaking Bloons due to its global range. It is recommended not to use the Sniper Monkey by itself early-game: it cannot attack fast enough to achieve high DPS until x-x-3 (Semi-Automatic), and its high damage is not very useful until ceramics start to appear on round 38 (round 32 in ABR)

Upgrades

Path 1

1-x-x Full Metal Jacket is a cheap Lead popper for rounds 28 and 30.
3-x-x Deadly Precision is easily affordable before round 40, and is an excellent counter to the MOAB. It can one-shot non-super ceramics, meaning it holds up very well into the mid-game.

4-x-x Maim MOAB is one of the best stallers in the game (alongside MOAB Glue), being able to hold MOAB-Class Bloons in place while slowly taking them out. Its relatively low price for its value allows it to shine on Impoppable and CHIMPS. Its effectiveness against DDTs makes it stay relevant into the late-game, though by then you should ideally have a more reliable counter (such as Super Glue or Icicle Impale).

5-x-x Cripple MOAB is not a bad tower, but its ineffectiveness against BADs, coupled with its rather high price, leave it in an unfortunate situation. While it is great to have, it usually is unaffordable before the mid-90s and so is seen less than its tier 4 counterpart.
Top path Sniper Monkeys benefit from both crosspaths. x-2-0's shrapnel allows the stun effect to hit multiple blimps at once, which is incredibly useful when dealing with large amounts of DDTs on Rounds 95, 97, and 99. It also gives the Sniper camo detection which can be useful if villages are banned or unable to be placed near the tower.
However, x-0-2 gives the Sniper Monkey more attack speed, which lets it keep blimps in place more effectively. This also increases its single target damage, making it more viable against the BAD on round 100.

Path 2

x-2-x Shrapnel Shot is a great upgrade against grouped Bloons, and is a great utility option in general. The direction the shrapnel goes is based on the angle of the bullet, so placing the Sniper Monkey directly in front of the track can increase DPS. This makes it less effective on maps such as Bloody Puddles where this is not an option.
x-3-x Bouncing Bullet is a strong mid-game option against densely packed rounds such as 55.
x-4-x Supply Drop's ability can be rather useful. Its ability to pop Lead Bloons also allows the Sniper to use the bottom crosspath without relying on a MIB.
x-5-x Elite Sniper is a useful mid-game tower. Its cheap cost allows it to perform well in spam strategies with Full Auto Rifles or Bouncing Bullets.
The middle path Sniper is best crosspathed with x-0-2: the attack speed outweighs the single target damage from Large Calibre and Full Metal Jacket's Lead popping is not needed.

Path 3

x-x-3 Semi-Automatic is overall a good tower, dealing good single-target damage. Crosspathing it with x-2-x lets it deal with early grouped rounds such as 36 effectively, as long as it is placed optimally. 2-0-3, on the other hand, is better against the MOAB (although using the top path is overall better).
0-2-4 Full Auto Rifle shines in spam strategies with Elite Defender and Elite Sniper, as well as Berserker Brew/Stronger Stimulant. This strategy works well for CHIMPS provided that the map is suitable; maps such as Pat's Pond make it very difficult to achieve good DPS with the shrapnel.
2-0-4 Full Auto is a great option for mid-game MOABs. Spamming 2-0-4s is a very good strategy against Boss Bloons (especially Vortex, whose shield it ignores).
x-x-5 Elite Defender is another great option. Its cheap price means it is affordable before round 40 (the first boss tier) with appropriate farming, making it useful for Bosses alongside Full Auto Rifle. On lower difficulties its ability to attack faster on life loss can be useful in the mid-game for otherwise-deadly leaks (although this is useless on Impoppable/CHIMPS)