Combat in FlexD6 is quick and managed in rounds. Because the game uses player facing rolls, there is no real need for initiative which is used in other games you may have played. Players and the Facilitator can determine the order in which characters go.
Roll to fight. See Rolling Dice. The single roll covers both the characters and the enemies attack. The enemy takes hits equal to # successes. The character takes hits equal to the enemy's Attack rating - # successes. See Enemies below.
Hits are temporary damage which add up and eventually cause an injury.
Characters take an injury and are KOʼd when taking hits equal to health - injuries. The character dies when taking their 3rd untreated injury.
A short rest will reset the character's hits to 0 and revive a KOʼd character. A doctor type skill can remove 1 injury once a day per character. It takes 2 days of downtime to remove 1 injury. Healed injuries turn into celebrated scars.
When hit and wearing armor, you can choose to reduce the armor points by one to absorb all damage. Armor can no longer be used when reduced to 0 points. At the end of combat, reset the armor points to the full amount. Next Level armor imposes disadvantage on all agility type checks. Also, small characters get +1 armor point and cannot wear Next Level armor.
Next Level: 3
Can be used to block all hits and cannot be used with 2 handed weapons. Roll 1d3 when taking to determine the number of blocks it provides. Must be repaired when reduced to 0 blocks.
Cover is an interesting challenge in many games, this included. When using cover, make it dramatic. Sparks fly! Splinters fly! A hole suddenly appears right next to the characters head. Make it dramatic and fun. From a mechanical standpoint, it changes how likely the character or enemy is to be hit in an attack.
Roll with disadvantage when attacking an enemy or character who's behind sturdy cover. Take a maximum of 1 hit when behind sturdy cover.
Enemies in this game only have 2 numbers which define them. The Attack Rating is used in combat and Health works just like characters. Enemies may also have abilities or qualities which change how combat flows.
Here's an example from a fantasy game:
Skeleton [H: 2, A: 1, W: Sword]: Ranged weapons have disadvantage. When KOʼd, a successful save will revive.
The Skeleton has 2 Health, an Attack Rating of 1 and is using a Sword as a weapon. The weapon is mostly for narration and information for the players and Facilitator. You can see where the Skeleton is more difficult to hit with a ranged weapon, so any ranged attack has disadvantage. Also, they may "rise again" if the Facilitator rolls a successful (likely 2d6 Check Die) save after the skeleton is KO'd.
Enemies fall into the following categories. When creating them, think about the threat rating, then consider these numbers.
Trivial: 1-2 Health, 1 Attack
Low: 3-4 Health, 1 Attack
Medium: 5-6 Health, 2 Attack
High: 7 -9 Health, 3 Attack
Heroic: 10+ Health, 3-4 Attack
For reference, a Medium enemy will be a challenge for a character with a 2 skill and some Advanced armor.
How do enemies attack? If the enemy gets a surprise attack or attacks in a way the character cannot counter, the attacked character gets a save (see Rolling Dice) to see if they can avoid the attack. If they successfully avoid the attack, they take no damage, but neither does the Enemy.
Does the character always take damage when failing to roll the number of successes for the attack rating? A character will only take damage if the enemy is attacking back. For example, let's say the enemy has a melee weapon and is charging the character from a distance. The character is using a ranged weapon and fires, but misses or doesn't match the enemy's attack rating. In this case, the character would not take a hit because the enemy can't counter attack. If the enemy was using a ranged weapon, then yes, the character would take a hit.
How many actions do characters get? There is no action economy in this game. Characters can move and attack or roll another test of some kind.