What's the difference between Damage and Reload Speed on a Rocket Launcher? Reload Speed costs $250 per point, and Damage costs $400 per point. They're also completely different upgrades, even though both of them enhance your overall damage per second. (DPS)

This is a bit of a technical read, fair warning. I'll add illustrations later.

There are some upgrades that offer you a substantial increase in return for each point you put into them; that is, every point you buy is worth more than the previous one. This is from the fact that, when your stats are increased (damage, projectile speed), etc. the increase is relatively less for each point. Going from 125% to 150% damage is a bigger increase than going from 150% damage to 175% damage.

On the other hand, upgrades that decrease an attribute (time per reload, time per shot) actually results in a larger stacking bonus per point you purchase.

As a general rule of thumb, upgrades that reduce something, whether its incoming damage or the time between shots, gain in value for each point you purchase in them. These are called exponentially increasing Upgrades.

How much additional benefit does each point of these upgrades bestow, though?

Primary Resistances (Bullet/Blast), at $300 each:
Point 1: 25% damage resistance, 33% effective health increase, 33% more than 0 points (Efficiency).
Point 2: 50% damage resistance, 100% effective health increase, 66% more than 1 point (Efficiency).
Point 3: 75% damage resistance, 300% effective health increase, 200% more than 2 points (Efficiency).


It costs $1800 to fully upgrade your Bullet and Blast resistance to the maximum. Any team member who is expected to spend more than a few seconds under fire (Heavy, Scout, Pyro) should focus initially on purchasing these upgrades, as it allows for the maximum lifespan, allowing the rest of your team a moment to rest and reload while keeping you alive. It is possible there are other, situational upgrades, but these are by far superior to most of the other upgrades for these classes in the early waves, with the exception of the Scout's Mad Milk.

The Heavy gets a base health of 1200 against non-melee targets, and can be buffed up to 3000 by a Medic with a maximum Overheal Mastery power. Not only that, he also recieves 300% more base healing from all sources.

THREE. THOUSAND. HITPOINTS.

If you want to get even more absurd, the Fists of Steel can give you a further 40% reduction to incoming ranged damage, resulting in an effective 5000 HP. And 375 HP versus melee attacks. That's the same amount as a Giant Heavy.

And if you want to get truly absurd, the Vaccinator adds another 75% resistance to damage, capping at 96.25% damage reduction. That's a total of 20000 HP. This isn't a particularly practical strategy for dealing with robots, just the maximum possible damage resistance to ranged damage. There is no Melee resistance, sadly.


Critical Resistance, at $150 each:

Critical hit damage functions differently from normal damage, in that the weapon will do its base damage (90-45 for a Rocket Launcher, 60 for a Scattergun), plus 200% of its base damage as determined done as critical damage, which is interpreted as "chemical" in the code. This is the damage type that Critical Resistance blocks. However, the damage will not be affected by falloff, which frequently increases the damage at range but can also decrease the base damage taken if you are so close that you would be taking ramp-up damage. The remaining non-crit damage is determined by your current resistance to the existing damage type.

Minicrit damage is also considered "chemical" crit damage, and can be resisted by this type as well, however, it can potentially be even more deadly due to the area-effect nature of the weapons (Sydney Sleeper, Extended Buff Banner) that cause it as well as the fact you can also recieve ramp-up damage against enemies buffed with it.

Point 1: 30% crit resistance. You take 200% * 70% or 140% extra damage on critical hits, and 35% * 70% or 24.5% from minicrits. 20% reduction in overall full crit damage. 25% efficiency.
Point 2: 60% crit resistance. You take 200% * 40% or 80% extra damage on critical hits, and 35% * 40% or 14% from minicrits. 40% reduction in overall full crit damage. 33% efficiency.
Point 3: 90% crit resistance. You take 200% * 10% or 20% extra damage on critical hits, and 35% * 10% or 3.5% from minicrits. 60% reduction in overall full crit damage. 50% efficiency.

Reload Speed (Clip-based weapons), at $250 each:
Point 1: 20% faster reload, 80% total time, 1.25x shots loaded. Efficiency: 25%
Point 2: 40% faster reload, 60% total time, 1.66x shots loaded. Efficiency: ~33%
Point 3: 60% faster reload, 40% total time, 2.5x shots loaded. Efficiency: ~50%

Firing Speed (All Weapons), variable cost; 100 for melee weapons and most secondaries, 200 for most primary weapons, 350 for the Miniguns:
Point 1: 10% faster firing speed, 90% delay between shots, 11% more attacks per second. Efficiency: 11%.
Point 2: 20% faster firing speed, 80% delay between shots, 25% more attacks per second. Efficiency: ~12.6%.
Point 3: 30% faster firing speed, 70% delay between shots, ~42.8% more attacks per second. Efficiency: ~14.2%.
Point 4: 40% faster firing speed, 60% delay between shots, ~66.6% more attacks per second. Efficiency: ~16.7%.

Consumable Recharge (Lunchbox, Throwable) at $250 each:
Point 1: 15% faster recharge, 17% more uses. Efficiency: 17%.
Point 2: 30% faster recharge, 42% more uses. Efficiency: ~21.4%
Point 3: 45% faster recharge, 81% more uses. Efficiency: ~27.3%
Point 4: 60% faster recharge, 150% more uses. Efficiency: 37.5%

Sub-Exponential Upgrades are how I describe upgrades that diminish in returns for each point you buy of them, that is, every point of these are worth less than the one before them.

Damage, at $400/$500 each:

Point 1: 25% increased damage. 25% efficiency.
Point 2: 50% increased damage. 20% efficiency.
Point 3: 75% increased damage. ~16.6% efficiency.
Point 4: 100% increased damage. ~14.3% efficiency.



Each point gives the same benefit.

Rocket Specialist, at $300 each:

All upgrade levels besides 0 give no damage falloff on direct hit, along with a stun effect.

Point 1: 15% increased radius on direct hit and rocket speed. 15% efficiency.
Point 2: 30% increased radius on direct hit and rocket speed. 13% efficiency.
Point 3: 45% increased radius on direct hit and rocket speed. 11.5% efficiency.
Point 4: 60% increased radius on direct hit and rocket speed. 10.3% efficiency.

For all upgrades which offer an increase in something, the first point offers the expected value, while subsequent points are worth less. For all upgrades that decrease something, the first point offers marginally more than the listed value for the first point, and more for each subsequent upgrade.

This means that, in most situations, maximizing upgrades that increase in effectiveness the more of them you purchase is usually the best decision. However, efficiency is only one way to compare upgrades. Reload Speed on a Heavy's Shotgun is worth considerably less than the same value into one of his other, more useful upgrades.

As well, it is not always beneficial to purchase just one upgrade type, as usually the waves of robots feature several different types of robots that you have to vary your attacking patterns for. Melee Scouts can be dealt with easily with just reload speed, but Superscouts require a different approach that usually involves Slow or Stun effects, or blocking.

Even if some upgrades are simply overall better than others, it's always important to consider the wave composition when choosing upgrades.