Post-Apoc Combat Reactions

Hey. These are just some rules I quickly wrote up in response to the idea that characters in d20 modern should be able to respond to things like Grenades, people moving out of cover, and whatnot. I'm hoping some of you can take these rules apart - keep in mind that they're being written for a smaller group, so they're not being written for publication or anything. Also, they use the d20 modern rules, but with classes designed by yours truly (mutations, too).

Combat Reactions
During combat, people have to react to situations quickly – dodging nearby grenades, ducking behind cover, and falling to the ground as bullets buzz overhead. The Combat Reaction rules here cover such behaviour.

What a Combat Reaction Is
Characters take combat reactions during the actions of other characters in the game. Combat Reactions can be made in several events:
Firing at an Enemy – a character can make a single attack against an enemy as a result of that enemy’s move.
Grenades – a character can make a reaction to a grenade that lands nearby.
Move – a character can take a single 5 foot step in response to an enemy’s attack.
Prone – a character can go prone as a combat reaction in response to an attack by an enemy.
In all situations, a character makes a combat reaction, which is resolved before the enemy’s action. Taking a combat reaction always costs an action point, and usually has another penalty associated with it (typically a loss of a move or attack action in the character’s next turn).
Characters cannot take combat reactions when flat-footed.
Characters can take combat reactions against combat reactions. For example, if a character took a five-foot step in response to a grenade attack, and thus opened himself up to a shot from an enemy that was previously unable to see him, than that enemy could take a combat reaction shot against the character.

Firing at an Enemy
If an enemy that was previously unable to be fired upon (for whatever reason) becomes a valid target (i.e., seen by the character and within attack range), the character can take a single shot against the target as a combat reaction. The character must fire whatever weapon is currently in his hands, and fires it in whatever mode it is currently set on (thus, a character could make an autofire attack as a combat reaction). In any case, the character suffers a –4 penalty on his attack when firing as a combat reaction.
If the enemy moves out from total cover and is fired upon as a combat reaction, he is considered to have partial cover for purposes of resolving reactionary fire taken upon him.
Firing as a combat reaction costs an action point. In addition, the firing character can only take a single action (either a move or attack action) in his next turn.

Grenades
If an enemy throws a grenade, all characters within 30 feet of where the grenade lands are able to take a single 5 foot step (presumably away from the grenade’s blast radius). Moving in such a manner costs an action point and a move or attack action in the character’s next turn.

Move
A character can take a single five foot step when being fired upon. The character can take this move to get behind better cover, for example. A character that moves from one degree of cover to another uses the average AC and save bonuses from those sources as cover. For example, a character that moves from One-Quarter cover (+2 AC, +1 Reflex) to One-Half cover (+4 AC, +2 Reflex) would gain a +3 bonus to his armour class, and a +1 bonus on all reflex saves. In any case, a character cannot gain total cover from a five foot step made as a response to an attack.
Concealment bonuses also use this averaging of results rule.
A character cannot take a five foot step in difficult terrain.
Moving in response to an attack costs an action point and a move or attack action in the character’s next turn.

Prone
A character can go prone as a combat reaction at any point. If going prone would put him in a situation of total cover, instead take an average of his degrees of cover, as detailed above.
Going prone as a combat reaction costs an action point.

You see, THIS is the kind of thing I like to see: extra-complicated house rules that are well-thougt-out and entirely implimentable in-game, but would never see publication in official sources because of their complicated nature.

It looks solid.

They are a little complicated, eh? I'm thinking of making them more streamlined (ie, they all only cost an action point), but I was thinking that'd make them used a bit too often (and the last thing I wanna see are things like this used EVERY round).

I just want to have a system that replicates the fact that grenades were typically used to flush people out of structures, rather than just blow 'em up. And a system that means when I dash from house to house, I can get shot. Y'know, things like that.

Yep, I know. And I LIKE it.

It's simple enough for my tastes, and its effects on the game sound quite enjoyable. It's just too complicated for mass appeal, or else we'd have already seen it published in official d20 rules.

Nice work. I'm stealing this idea, for the post-apoc games I can never convince my friends to play.

Interesting.. my first thought is 'hey, expanded AoO rules!'
My second though was, 'this looks like a good implementation of adrenaline in combat'

Which may not be a bad thing, perhaps alter to use AoO's instead of Action points, and maintain the mechanic that a Combat Reaction burns your next Move action *or* an Action point.
Another Combat Reaction may be taken in a turn at the cost of another AoO and either becoming Fatiqued or an Action Point. {GM can limit number of Action points spent in this manner}

This would allow character to use this options alot, but still have uses for the precious Action points. It also allows a Combat Reflexes build to be extremly dangerous for a single round.

You can trim down the list of options to:
As a Combat Reaction you can do one of the following:
- Snap-Shot: Make a single ranged attack with a weapon already in hand. This attack suffers a -4 penalty to hit
- Move for Cover: Move 5', Drop Prone, or stand from Prone
--- If cover is available where the character moved to, they gain a bonus of +2 to AC and +2 to REF save for the attack they are reacting to.
- Grab: Dropping whatever is in your hands, you may grab either gear or an ally. Grabbing gear allows you to draw an item. If attempting to save an ally, you must make a touch attack. A willing ally can change his Dex mod to AC to be negative, making it easier to grab him.

A combat Reaction is resolved immeditely upon announcment. This allows characters to interupt an opponents move mid-way. A counter Reaction can be announced that would interupt the first. A character whose intended action is no longer valid must select another legal action or abandon thier action.

I don't think you will see this stuff used every round. Each option has a penalty associated beyong losing your next Move action.
Avoiding the 5' step rule in the text of the Move for Cover option means you can't use this to avoid sword weilding maniacs.. they would get an AoO as you retreat.

However, this variant does make Combat Reflexes almost a neccessity for the tank build.
I can't see going with just Action points as the limited number of points means players will be less likely to remember the rules when there is a chance to use them.

Silly/extreme example:
Joe opens the door to the room and Fred Snap-Shots at him. Joe burns a Combat Reaction to step back 5', out of sight. Fred burns a Combat action to move back into the line of fire..to which Joe burns another Combat reaction to close the door. Fred is left with the choice of firing into the door and giving up his attack. After which Joe continues with the rest of his turn.
{In this example both sides have Combat Reflexes and end up using a Move action and an Action point.}

Not so silly example:
Fred and Joe are standing at the edge of a cliff, with 10' seperating them. Sally pushes Joe and he is about to fall. Fred burns 3 Combat Reactions, 2 Moves and 1 Grab. Since he is out of Action points his second and third Reactions will Fatigue him. He successfully snatches Joe from certain death, but ends up Exhausted.


The more I think about this, the more fluid these mechanics would make the battlefield. It would be harder to run combat with lots of characters. The key would have to be making Reactions as simple/fast to execute as possible.

Hm. See, I've never really used action points, so I have no idea how often they're used in-game. I do like the idea of there being a synergy between combat reflexes and combat reactions - I'll put that in, or something.

I should mention that combat reactions can only be done during your turn. I do need to figure out some sort of rule to keep them used only once or twice a combat, though - I think the idea of letting them be normal actions that cost an action point (and cost your next action) is a decent enough balancing factor, though.

Thanks for the feedback, Screwhead. And I agree - too many characters WOULD slow down combat to a crawl. Luckily, with the game I'm running, combats are usually just the PCs and 1-3 NPCs. And since most NPCs don't have action points, only the PCs will use the options most times.

The use of action points depends alot on how you refresh them. The standard Eberron rules have action points refreshing at the start of a level. This means out of the 14 average encounters to reach the next level, they have 5 or so action points to spread around.

I like the idea of Combat Reactions being available for everyone as it spices up the combat and will keep players more engaged during a combat round. I also like the idea of Action Points allowing characters to do heroic stuff like rush over to the cliff to save thier buddy.

Wik said:

I should mention that combat reactions can only be done during your turn.

Click to expand...

This invalidates the whole point, as I understand it, of Combat Reactions. These are actions you take outside of your turn in response to an opponent or event.

You could add a 'Combat Reaction Pool' which is the number of Reactions you can perform in one encounter. If you tie it to the adrenaline reponse it could mechanically be CON Mod, altho this would tilt things in favor of barbarians a bit. Alternatively you could tie it to combat prowess by using the number of iteratives the character has in a full attack. This would tilt a bit in the Monk's favor...
In order to link in Combat Reflexes into this pool, have the feat add the Wis Mod to the Reaction Pool.


meh, personally I would stick with AoO plus choice of: Sacrifice next Move, Burn Action point, Become Fatigued. Mainly because I like a more fluid battlefield

Primitive Screwhead said:

This invalidates the whole point, as I understand it, of Combat Reactions. These are actions you take outside of your turn in response to an opponent or event.

Click to expand...

Yeah... I screwed up. I meant to say "CANNOT be used during your turn". My bad.

Primitive Screwhead said:

meh, personally I would stick with AoO plus choice of: Sacrifice next Move, Burn Action point, Become Fatigued. Mainly because I like a more fluid battlefield

Click to expand...

Actually, that ain't bad. Players with combat reflexes could make multiple combat reactions, then (which is fine by me), although if they did, it would definately cost them at least an action point.

YEah, I could go with that. I'll re-work things. I like this idea.