Velocity

Velocity is how fast a projectile travels, counted in pixels moved per tick. It has nothing to do with use time, which is how often you can swing. A tile is 16 pixels and a second is 60 ticks, so a velocity of 1 works out to 3.75 tiles per second, or 5 mph on the Stopwatch.

In play this is the stat that decides how far ahead of a moving target you have to aim. A slow projectile against a dashing enemy means leading the shot by half a screen and missing when the enemy changes direction. A fast one lets you aim at where the enemy is. Distance makes the difference worse, so velocity matters most in exactly the fights where you want to keep your range.

Some projectiles carry a second, invisible property that decides how many times per tick they move by their listed velocity. It counts up from zero, and zero means no multiplier, which is the normal case. A value of 1 makes the projectile move twice per tick, 2 makes it move three times, and so on. Two arrows with the same printed velocity can therefore travel at completely different speeds, which is why comparing raw numbers between ammo types is misleading.

The order of operations is fixed: add the weapon velocity and the ammo velocity together, then apply the multiplier to the sum. The multiplier is always last.

• A Platinum Bow at 6.6 firing Jesters Arrow at 0.5 sums to 7.1, and the arrow's doubling takes it to 14.2.
• A Chlorophyte Shotbow at 11.5 firing Wooden Arrow at 3 sums to 14.5 with no multiplier, so 14.5 is the final figure.
• The same bow firing Jester's Arrows sums to only 12, but doubling takes it to 24, well past the plain wooden result.

That last pair is the useful lesson. Ammo with a low printed velocity and a multiplier beats ammo with a high printed velocity and none, and a slow bow benefits from a multiplier far more than a fast one does.

The Magic Quiver raises the multiplier of any arrow that has less than one, which in practice means it doubles the flight speed of nearly every arrow in the game. It does nothing at all for arrows that already sit at one or higher, so slotting it while shooting Venom Arrow buys you the damage bonus and no speed at all. If you are choosing ammo around the accessory, the plain fast-flying arrows gain the most from it.

• Ranged prefixes can raise velocity. On the Flamethrower and Elf Melter that reads as extra range rather than a faster-looking stream.
• A prefix cannot touch the speed of anything a magic weapon fires, so reforging one is purely about damage, use speed and mana cost.
• Melee speed bonuses do raise the velocity of melee projectiles, which is why boomerangs feel snappier under an attack speed buff.
• For beam weapons like the Shadowbeam Staff, the multiplier sets the beam's length rather than making it arrive sooner.

A handful of weapons, mostly magic, vary their speed over the projectile's life. Demon Scythe starts slow and builds up, so it is unreliable up close and fine at range. Death Sickle does the opposite, slowing until it hangs in place and vanishes, which gives it a hard maximum range regardless of where you aimed. The Magical Harp scales its notes to how far the cursor sits from you, though even at full stretch they are slow.

Most projectiles lose a large chunk of their speed the moment they enter water, and flame-based ones are usually destroyed outright. Since projectiles also expire on a timer, a slower projectile covers less ground before it disappears, so a submerged fight quietly shortens the effective range of everything you own. Anything affected by gravity also drops harder once slowed, so shots that were flat on land start arcing into the floor.