Combat Rules & Clarifications

Massive Criticals

A critical strike should feel like a big moment, so it is always sad when damage is rolled for one and it is still low. As such at this game critical hits will be treated slightly differently. If you roll a critical hit then you deal damage equal to the maximum damage of your weapon/spell + another roll of the damage dice.
For example, let's say Billy the fighter who has a +4 to strength lands a critical hit with his longsword. The longsword has a damage dice of 1d8 so Billy the fighter deals 12 + 1d8 of damage to his target.

Flanking

As it stands in the PHB, Flanking is an optional rule, and a very powerful one at that. Currently, if you are flanking an enemy you get advantage on the melee attack roll to hit the target. This is mathematically equivalent to a +5 to the roll. Though this does look powerful, the spirit of tactical play is important to combat in the games that I run.
In this game when you are flanking an enemy with an ally you will instead receive a +2 bonus to the attack roll. This rule still awards tactical play, showing that it is difficult for an enemy to defend against multiple targets, while also not going too far. This rule also allows for the flanking bonus to be stacked with other effects that would normally give you advantage on the attack roll.

Grappling 

Here are some clarifications to the grappling rules:

• A creature grappling a creature of its size or smaller can move up to half its speed, dragging the other creature with it.
• Both a grappled creature and the creature grappling it have advantage to melee attack rolls against one another. They also have disadvantage on ranged attacks against one another.
• A creature that successfully uses its action to break free of a grapple can immediately use a bonus action to attempt to grapple the creature that had been grappling it, so long as you are able to grapple the creature to begin with.
• A creature that is grappling another creature can use their action to impose the restrained condition on the grappled creature until the start of their next turn.
• A grapple, as well as a shove or trip attack, can be made as an opportunity attack.

Firearms

Firearms are unlikely to make an appearance in this adventure unless the players encourage the world to go that direction. If they do appear Fighters, Rangers, and Rogues may also have proficiency with the item if it makes sense for their backstory, or encounter them in the game and take either the weapon master feat from the PHB, or the Gunner feat from TCE.