BattleTech Game Design Random Ideas

Kaiju vs Mecha

kaiju_300In a post a couple of months ago, I mentioned that my brother and I were working on a kaiju vs. mecha game inspired by Pacific Rim. We used the rules for BattleTech as a starting point and then whittled away a bunch of the complexities to try to get to a simpler core system. Our goal was to create a set of rules for playing a fight between a small number of kaiju and mecha that could potentially be expanded with other unit types (tanks, helicopters, swarms of smaller monsters, etc) and a campaign system.

Simplifying The Turn Structure

One of the things that can make BattleTech games take a long time is the way that its rounds are subdivided into phases that require a fair amount of inter-phase bookkeeping. As an example, attacks are declared in one phase, then actually resolved in the next phase of the turn. In my experience, those inter-phase dependencies add a lot to the complexity of the game, are annoying to track, and make the game a bit slower to play. Because of that, one of my first goals was to simplify the structure of each round and minimize the amount of bookkeeping needed.

I eventually settled on a 4 phase structure for each round of play:

  1. Initiative Phase
  2. Movement Phase
  3. Action Phase
  4. Maintenance Phase

Initiative Phase

The first phase of each round is used to determine which side of the conflict has a temporary advantage over the others. Each player rolls 2d6 and totals the result. The player with the highest total has the initiative for the turn. Reroll any ties until one player wins the roll. Having the initiative represents having an edge over your opponents that allows you to better react to his or her actions.

Movement Phase

Most movement of mecha and kaiju on the game board happens during the second phase of each round. The player who doesn’t have the initiative chooses a single unit from her force and moves it. Then the player with the initiative moves one unit from his force. The players then continue to alternate moving one unit at a time until all units have been moved.

Action Phase

The third phase of each round is when mecha and kaiju make attacks and perform other actions. The ordering in the action phase is the reverse of the movement phase, so the player who has the initiative goes first. He chooses a single unit from his force and makes any actions with it that he wants. His opponent can then perform actions with a single one of her units. The players then continue to alternate activating one unit at a time until all of their units have had a chance to act.

Maintenance Phase

The last phase of each round is used for any end of round bookkeeping. The main thing that happens during this round is that mecha who have accumulated too many energy points check to see if they experience a malfunction and kaiju recover stamina points.

Adding an Action Economy

One big addition to our rules was adding an action economy to the game. Each action that a unit can perform has an action point cost. For example, making a simple attack might cost 1 action point. Each type of unit has a different set of rules around the number of points they can spend in a round.

Mecha gain energy points for each action they use in a round. At the end of a round, if they have more energy points than their safe reactor output, then the player needs to roll to see if the mecha suffers malfunction with higher numbers of energy points making malfunctions more likely.

Kaiju on the other hand spend their stamina points when performing actions. At the end of a round, they double their current number of stamina points up to their maximum amount. That means that a kaiju can safely take a lot of actions in a round but then might take a couple of rounds to recover its breath where it is limited to only 1-2 points worth of actions.

Mecha and Kaiju Stats

Another part of simplifying BattleTech was making the units less complex. Some of this came easily because we wanted kaiju and mecha to be built around a couple of trademark abilities rather than bristling with weapons and systems like BattleMechs, but we also made decisions to reduce the number of hit locations and use lower numbers of armor and structure points.

Fire King

Type: Kaiju

Speed: 4 walk (Leg Joints)

Max Stamina: 6

Each unit has a few core bits of information: Name, Type, Speed, and either Max Stamina (for kaiju) or Reactor Output (for mecha). Name is just the unit’s name. Type indicates whether the unit is a kaiju or a mecha. Speed provides the number of movement points that the unit gets. There are a few different types of movement points (walk, fly, jump, and swim), and the piece of equipment that provides the movement points is also listed for easy reference. Max Stamina is the maximum number of stamina points that a kaiju can have at the end of each round. During the maintenance phase, each kaiju doubles their current number of stamina points up to its maximum. Mecha have a Reactor Output stat instead that is the number of energy points they can gain each turn without risking a malfunction.


Hit Locations: 11, 12

Armor: 6

Internals: 3

Destruction: Death

Damage Transfer: NA

1. Brain

2. Sensory Organs

3. Jaws

Next, the unit has a list of body locations with details on each. Fire King has 5 body locations (Head, Torso, Right Arm, Left Arm, and Legs), but different units can use different sets of locations. Each location’s entry contains a few pieces of information. Hit Locations represent how likely a given body location is to be hit by any given attack. Each time a unit is hit, the attacker rolls 2d6 and then consults the hit location entries to determine which location was hit by the attack. In this case, Fire King’s head is hit on a roll of 11 or 12. The next two location stats are Armor and Internals. These represent how much damage a location can take before being destroyed. When a unit takes damage, it loses first armor points then internal points. When internal points are lost to damage, there is also a chance of a critical hit. When a location is destroyed it may have a special effect specified. In this case, Fire King dies when his head location is destroyed. If the losing the location doesn’t result in death, then the Damage Transfer entry for a location will specify what location will take damage on future rolls of its hit location numbers. Finally, a location has a list of equipment that it contains. This list is used to determine which system gets damaged when the unit suffers a critical hit to the location.

Adrenal Gland (Torso): Fire King’s adrenal gland allows him to perform two special actions: Fury and Lunge.

Fury (Reaction; AP 1; Fury may be used when Fire King hits with an attack): The triggering attack deals 2 extra points of damage.

Lunge (Standard; AP 1): Fire King moves up to its land speed. This action may only be used once per round and may not be used during a round when Fire King also used the Run action.

The final part of a unit’s stats is its list of equipment. Each piece of equipment provides different benefits that could include either static bonuses or powers. Powers can be either movement powers (used when a unit is moved in the movement phase), standard powers (used when a unit is activated in the action phase), or reactions (specify a special trigger such as hitting with an attack or being damaged). Our goal is to have the equipment be very modular so that eventually we can have rules for changing or upgrading equipment throughout the course of a campaign.

By Scott Boehmer

A game enthusiast and software engineer.

2 replies on “Kaiju vs Mecha”

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