The dart gun replaces the bow. The crafting recipe will be added as soon as I get access to a computer. Basically, you use it using darts as ammo. You can use the arrow crafting recipe to get 8 darts. A dart gun is like a bow, but cannot get beyond half-charge, so it can't deal more than 5 damage, just enough to kill a Red Bloon. The upgrades are:

Path 1

Long Range ($90, allows the gun to charge up to 7 damage.)

Laser scope ($120, allows the gun to charge up to 9 damage and lets you see invisible things.)

Triple Darts ($330, you can set the gun to shoot 1-3 darts at a time, more darts obviously takes up more ammo.)

Super Monkey Fan Club ($8000, Special Ability: All Dart Monkeys gain Super Monkey Armor for 15 seconds.)

Path 2

Piercing Darts ($140, darts will go behind the first target after dealing damage, unless the target was a blimp, so that they can hit a second target.)

Razor Darts ($180, like Piercing Darts but darts will go behind the second target as well.)

Spikey Cannon ($500, can now be set to shoot spiked balls (iron ingots in an x shape to craft). They are 2x2 blocks that roll 50 blocks or until they hit a blimp or a block they can't mine. (When they hit a block, it acts as if it had instantly been mined with an iron pick for 5 seconds.) They deal 15-20 damage!)

Super Spike Cannon ($1500, spiked balls do 20-25 damage, mine twice as much, roll 100 blocks, will not stop for blimps weaker than B.F.B.s, is 4x4, and penetrates armor for ceramic, metal, and frozen bloons.)