Monday, April 10, 2023

Reactor Breach

Tanked - Dofresh



It's The Future. Oh No. You have a mechanised combat exosuit, and the urgent need to use it. You'll be fighting other mechs, giant monsters, friends, enemies, and yourself. Good thing the eject lever always* works.

Your mech has:
  • Four (4) limbs, usually an equal number of arms and legs
  • Two (2) weapons, and is heavily customised to utilise them both
  • One (1) unit of additional equipment, such as a drone, a few grenades, a sidearm, or a specialised tool
  • One (1) Power Reactor
  • Basic life-support
  • Two-way comms
  • One (1) pilot

Choose one die that represents your mech size, from d6 (big), d8 (giant), d10 (massive) to d12 (gargantuan). Use it whenever you need to make a "Size Roll". Larger mechs are tougher and hit harder, smaller mechs are nimble and accurate.

Your mech handles all the ammo, fuel, coolant and power you'll need for normal operations. You'll only need to keep track of what things are going wrong: any limbs that disabled or destroyed, your current Heat level, any ongoing dangerous conditions, and any resources you might run low on during abnormal operations.


Stabbing: When fighting hand-to-hand, both side makes a Size Roll, highest deals damage. If the opponent that rolls higher isn't in any position to inflict harm for some reason, nothing happens.

Shooting: Must gunplay does not involve any dice rolls. Unless a ranged attack is totally from surprise, or at point-blank, there is always a chance for the target to run for cover before taking damage. If they don't find cover, they get hit. If a mech is being shot at from multiple sources, it is unlikely they will be able to find enough cover to block everything. Running through suppressing fire requires a Size Roll of 3 or lower (normally).

If for some reason you need to shoot something with great precision, and have enough time to aim, make a Size Roll. The closer to 1, the closer to bullseye.

Bleeding: When an attack lands, the victim still gets to decide where it impacts, whether on a limb or on the central chassis. The first hit disables a limb, but field repairs are still possible and it can still be waved around like a club. A second hit to the same limb destroys it completely. Weapons will always have interesting additional effects on a hit, to be determined on a case-by-case basis by all players.

To determine the effect of a Chassis Hit make a Size Roll:
  1. Reactor Damaged, further damage to the Reactor will cause a Reactor Breach.
  2. Reactor Damaged.
  3. Mech inoperable for one round.
  4. Pilot Injured, further injuries will be worse.
  5. Pilot Exposed, can be killed if directly targeted.
  6. +5 Heat.
  7. +5 Heat.
  8. or more: Paintwork Scuffed.

Grabbing: If you want to grapple, trip, disarm or otherwise impede an opponent, declare your intention before engaging in hand-to-hand combat. If you succeed the Size Roll, it happens. However, your opponent should declare a matching impediment or other penalty, which happens if they succeed. Each outcome should be modified by the tactical situation, the specialities of the mech, and the weapons at hand. The outcomes should be fair, rather than being equal.

Any ties are resolved by doubling the stakes and rolling again. After figuring out the next stakes, either opponent can instead bow out gracefully instead of rolling.

Grenades: Any mech caught in the blast-radius of a grenade takes one automatic chassis hit. Close-range blasts can result in up to three chassis hits, a grenade exploding on the inside of the mech causes a mess.

Drones: An active drone counts as an extra weapon that the deploying mech can direct. Drones have a Size of d2 and no limbs, they are extremely nimble but very fragile.


The top speed of every mech is almost exactly the same. It's just a thing. What is more important is acceleration and manoeuvrability. If one mech is trying to flee another, or when multiple mechs are attempting to out-manoeuvre or out-pace the others, they all make a Size Roll. Lowest roll is most successful.

Climbing, crawling, or swimming requires a low Size Roll to do so quickly and precisely.

A mech with less than two fully functional legs can limp or crawl at low speed.

During a round, any mech can run practically anywhere within a normal field of engagement. When determining whether a mech can or cannot reach a particular point, the distance is less important than the obstacles, corners, cover, suppressing fire or line of sight they interact with. Grappling a mech is a great way to lock down a slippery opponent.

Initiative: Whichever team has a greater total tactical advantage goes first each round. Intel, leadership, high ground, spotters, strategy and many other factors can influence initiative.


Your Mech is already running on the absolute margin of what it can withstand. If you want, you can push it further, but this will accrue Heat:
+10 Heat to take 3 full actions on your turn.
+5 Heat to dodge an attack at the last instant.
+5 Heat to take an action before any other mechs.
+5 Heat to do something else with your mech that you probably shouldn't.

As an action, you can Vent Heat to set Heat to 0, but this a) creates a huge obvious cloud of steam and b) completely disables your Mech for a few seconds. If you Vent Heat in range of any enemy that is facing towards you, it can make a free attack against you, which requires no roll to hit and lands exactly in a location of their choice. This can destroy a weapon or hit an exposed weak point, potentially destroying a Mech in one go

At the end of any turn (including enemy or ally turns!) that you gained Heat, roll 1d20+Heat:
  1. or less: Nothing
  2. Safety Margins Exceeded. Multiple irritating alarms go off.
  3. Warranty Voided
  4. Recalibration Lag. Your mech stumbles badly, or falls over.
  5. Magic Smoke. One auxiliary function stops working: incoming comms, outgoing comms, door controls, missile lock detection, aircon.
  6. Burst Tubes. Coolant system damaged, Vent Heat reduces by 10 rather than removing all.
  7. In The Hot Seat. Cockpit starts getting dangerously hot.
  8. Ammo Jammed. Weapon cannot be used until it is manually cleared.
  9. Bearings Seized. One limb locks up until you Vent Heat. If you use it anyway, it'll be disabled.
  10. Have You Tried Turning It Off And On Again? Unless you stop your mech and power down for a whole round, at the end of next turn roll 2d20 on this table (not adding Heat).
  11. Controls Locked. Next round, your mech will repeat the exact same actions again.
  12. Wiring Fried. Every action you take has a 3-in-6 chance of doing something completely different. Drops to 1-in-6 after you next Vent Heat.
  13. Run Dry. Coolant system no longer works, you can no longer Vent Heat
  14. Cooking Off. One firearm starts firing repeatedly and cannot be stopped until it runs out of ammo.
  15. Reactor Overload. +10 Heat at the start of next round.
  16. 'Twas I That Set The House Ablaze. Catch on fire. +5 Heat at the end of each round until you put it out. Stop, drop, and roll!
  17. Reactor Meltdown. +5 extra Heat any time you gain Heat, until you get it repaired.
  18. Shutdown Imminent. At the end of each round 50% chance that your mech stops working completely.
  19. Reactor Critical. Mech explodes in the middle of the next round.
  20. PEBKAC. Control panels start exploding inside the mech.
  21. or more: Reactor Breach. Mech explodes immediately.

If you're feeling brave, you can gain +10 Heat, take two actions, and use the third action to Vent Heat. Keep in mind that if you have failed to defeat your opponent, you will be in serious danger!


  • Battlefield locations are often a compromise between all involved. Every player should add any amount of features to the terrain map that they wish, before determining where each mech starts. Consider adding barriers, paths and transitions to the map: forests, bogs, mountains, valleys, buildings, roads, train-tracks, impact craters.
  • If you pick up a dropped weapon from a fallen mech, it has enough ammo left for one or two shots. Weapons need extensive work before they can connect and be reloaded by a different mech.
  • Trash-talking your opponents over an open channel is traditional.
  • Orbital weapons can be hired for a relatively modest fee, or would you like to purchase a subscription to Tungsten Strike Plus? First month comes with free Same Minute Delivery!


  1. In the desert, in a shack, is a briefcase. It is vitally important that the briefcase is recovered intact. Mech-sized weapons will blow it up. Everybody wants the briefcase. Two teams, one target. Blue Team has the high ground but Red Team is closer, go go go!
  2. Race-day at the Mech Arena! Pose as racers and watch out for saboteurs. There is a mission here but you'll only find out after the first lap is finished.
  3. Don't you know there's a war on? Insurgents, pro-surgents and ex-surgents have encountered each other in the streets. Mission goals include A) survive b) prevent war-crimes (smile, you're on camera!) and c) get paid.
  4. The local mech-repair garage is a year behind on rent, various other debts have piled up as well. Where there's money missing, there's money to be made.
  5. An important diplomat has suffered a ruptured appendix, liver and spleen while in the middle of a warzone. His medi-pod is blast resistant and supremely gimballed, it can be thrown around like a football. You'll need to, since pro-war forces are approaching, but they won't fire the first shot, ever.
  6. Ostensibly, the mission is to protect this city, or whatever. In reality, the city has long been abandoned and you should use this as an excuse to beat the crap out of each other. Points will be awarded for the successful defence/destruction of the city, but like, only nerds care about that sort of thing.
  7. Choo choo! A train is approaching the shunting yard carrying high explosives. It arrives in five rounds, and it's really important that it gets from this side of the shunting yard to the other side. Once a train has left the station, even a mech cannot keep up. Watch out for the bullet train! And the train containing fissile material! And also all of the other trains! Trains trains trains!


  1. Limb-Integrated Weapons are larger, more dangerous, and installed in place of a hand. They can still be partially used if that limb is disabled, but accurate aiming is no longer possible.
  2. Spinal-Mounted Weapons don't need a limb to fire, and are deeply buried and shielded. They must be targeted very exactly to be damaged. However, they can only be fired in the direction the mech is facing.
  3. Shoulder-Mounted Weapons can be fired in any direction without a limb, but are relatively easy to destroy. Some small weapons are Head-Mounted and are very accurate.
  4. Jetpacks or other modifications allowing fully-controlled flight at mech-appropriate specs. Hoverboards anyone?
  5. Remote Control
  6. Single-Use Teleportation Node


  1. Highly unreliable psychic powers. Requires direct eye-contact, can cause brain haemorrhages, but very useful for converting the enemy to your side.
  2. Supremely competent master assassin. Cannot be hit by any attack so long as they keep moving.
  3. Another, smaller mech. d4 size, no weapons. Who could possibly pilot such a thing?
  4. A ghost, the bones of their former body linked to the control surfaces of the mech.
  5. Amorphous grey sludge, mostly blind and weak to extremes of temperature. Selectively conductive, can crawl inside other mech chassis and take control.
  6. Remote controlled, a box of wires in the seat with a blinking red light and numbers: 0:03, 0:02, 0:01...


  • Choose one dice for all Size Rolls, d6 big, d8 giant, d10 massive, d12 gargantuan.
  • Stabbing: Contested Size Rolls, highest wins and deals damage (if that is at all possible).
  • Shooting: No rolls, target has a chance to find cover, otherwise they get hit.
  • Precision: If you have time to aim, Size Roll closer to 1 is closer to bullseye.
  • Bleeding: The target chooses where an attack lands (most of the time), on an arm, leg, or the main chassis. First hit to a limb mostly disables it, second hit destroys it. Hits to the chassis have a random effect, making a Size Roll.
  • The Chase: Mechs trying to chase or outmanoeuvre each other make contested Size Rolls, lowest wins.
  • A mech with less than two fully functional legs can limp or crawl at low speed, but has no chance of keeping up with intact opponents.
  • Initiative: Whichever team has a greater total tactical advantage goes first each round. Intel, leadership, high ground, spotters, strategy and many other factors can influence initiative.
  • Your Mech is already running on the absolute margin of what it can withstand. If you want, you can push it further, but this will accrue Heat.


  1. Nice! Soon you'll have rules for every genre. :)

    The rule for resolving ties is pure genius, by the way. I really want to use that somewhere.

    1. You mean I'm missing a genre!?!

      And cheers, I think the tie resolving is something I'll start using everywhere

  2. I really like this :). I've been working on some Mecha stuff as well, this feels fairly compatible with the stuff I've been developing. Like just bolting my Gear system (based on Saker Tarsos' Concept Crafting) to this, or the crunchier bits of this to my Mecha, and they'd go together pretty well I think.

    1. Yeah flexibility is a key point here, the Size Rolls are basically the only real "mechanic". It could do with some more content though especially some good non-weapon equipment.

  3. Love it! Between this, Chris McDowall's "MAC Attack", and redownloading Titanfall 2 on Xbox, I'm on a huge mech kick.

    1. I wouldn't want to compare this and MAC Attack :D (because I'd lose ofc)
      Thank you for your comment!