Ultra-Tech: BFG9000

Ultra-Tech: BFG9000

Sometimes you need a big gun. And do you know a gun bigger than BFG9000 from Doom? Here's my attempt to convert it to GURPS and this is probably the case where you shouldn't convert the exact mechanist and just stat it up as a cone attack, but I decided to try to make it closer to the original source. Some numbers probably should be tweaked, mechanics simplified, but it still works, although clunky, right?

BFG9000

BEAM WEAPONS (RIFLE) (DX-4, or other Beam Weapons-4, or Guns (Rifle)-4)

To fire a BFG you have to take a Ready maneuver to charge it up and an Attack maneuver on the next turn. When you fire a BFG9000, you fire a primary projectile that travels at Move 20 towards the target. When it reaches the target or collides with an obstacle or other target, the BFG9000 releases a spray of rays in a 30° cone in the direction you are facing. Treat this as Spraying Fire (B409), but with no Recoil increase, and when splitting up your RoF, you cannot assign more than a half of your RoF to a single target, unless it is close enough to you (has a Size Modifier high enough to completely counteract the range penalty, as stated in Rapid Fire vs. Close Stationary Targets (B408)). If two or more primary projectiles reach their targets simultaneously, the BFG9000 releases a number of spray equal to the number of primary projectiles that have reached their targets this instant.

            The primary projectile moves at the start of your turn. Since it is a relatively slow projectile, other creatures are able to intercept it. If a creature enters the hex with the primary projectile, or if the projectile moves through a hex occupied by a creature, it might be hit by the projectile. Use the Hitting the Wrong Target (B389) rules. Additionally, the original target can move away during the projectile’s flight. Thus, the shot will be considered a miss, if the target is not immobilized as it further than 20 yards from you, and to hit you will have to use the Hitting the Wrong Target (B389) rules. Creatures can even deliberately intercept the primary projectile, using Slam (B371) rules as if the projectile has SM-4.

            Example #1: Characters B, C, and D are robbing character A in a dark alleyway; they are threatening him with knives. Character A takes out his BFG9000 and takes a Ready maneuver to charge it up. B, C, and D stand there in shock for one second, confused by the size of the gun.

On his next turn, A makes an Attack maneuver, targeting D. A has Beam Weapons (Rifle)-14, and rolls 9. Since the distance between A and D is 11 yards, A’s effective skill is lowered by 5, but it’s still enough to hit. D is within 20 yards, and that means that the primary projectile reaches him this second. D fails his Dodge roll and is hit by the primary projectile in the torso.

D is wearing a DR 60 clamshell armor, even though he is just a thug. A rolls 70 damage. The primary projectile has an armor divisor (2) and it deals 40 points of injury to D. D fails his HT roll and falls unconscious, barely alive. C is in 5 yards from D, so he is dealt 70/(5x5)=2 damage, but his armor absorbs it.

Then the BFG sprays its secondary rays. A is facing north, so it sprays rays in a 30° in that direction. Unconscious D and unharmed C are caught in the cone. Since both of them are too far to take all the rays (an SM+0 creature can only do so at a distance of 2 yards or less), A splits his RoF, assigning 1 shot to D to possibly finish him off and 4 shots to C. Note that 5 shots are wasted, because D and C are 5 yards apart. First he makes a RoF 1 attack against D. His effective skill is 7 (extra -2 because D is lying down), and he luckily rolls 7, burning the body further with a ray. The ray’s damage is 50 with an armor divisor (2). D in dealt 20 more injury; he fails hit death roll and dies in flames. Then A makes a RoF 4 attack against C. He gets no skill bonus from RoF this low and gets a -4 range penalty. A rolls 8 against his effective skill of 10, hitting with 3 shots from 4. He rolls 39, 42, and 27 for damage. C wears a light clamshell with DR 45, and he receives 17+19+4=40 points of injury, which is enough to kill him on a failed HT roll. B runs away after seeing this.

Example #2: This time the thugs engage in combat from a longer distance. A takes a Ready maneuver to charge his big gun up and makes an Attack maneuver next turn, targeting D. The distance between them is 27 yards (-7 range penalty), which brings A’s effective skill down to 7. But since the primary projectile cannot cover 27 yards in one second, this shot automatically is considered a miss for now, but will still have a chance to hit D next turn, provided that D doesn’t move away.

But D moves away from the projectile and a bit closer to the shooter. B and C are not as immobile this time and move closer to A, planning to stab him.

On A’s turn the primary projectile continues its flight and flies off screen, but still doesn’t collide with anything. A runs to hide behind the corner. B and C take the bait and follow him.

And on A’s next turn the primary projectile hits a wall of some building, which forces the BFG to release its deadly rays. C is within 1 yard of A, which allows A to assign more than a half of his RoF to C. He decides to fry C with all 10 shots, assigning 0 to B. A rolls 8 against his effective skill 16 (he gets a +2 bonus from high RoF), and hits with 9 rays. He rolls 41+30+37+35+33+27+34+42+36 damage. C is wearing his DR 45 clamshell armor again, and he receives 18+7+14+12+10+4+11+19+13=108 points of injury and most of his body instantly turns to cinders, leaving only some small chunks of charred flesh.

A takes a Ready maneuver to charge his BFG up again, and it’s enough to make B run away in terror.

            Cost Justification

Let’s use Metatronic Generators from Pyramid #3-46. First we’ll have to stat the attack up using advantages. I wasn’t sure on some of the modifiers, but it’s just an approximation.

BFG9000 [295]: Burning Attack 20d (Accurate 1, +5%; Armor Divisor (2), +50%; Extra Recoil, Rcl 2, -10%; Increased Range, x50, +50%; Limited Use, 4/day, Fast Reload, -10%; Nuisance Effect, Slow, -30%; Takes Extra Time 1, -10%) [145] + Burning Attack 10d (Accessibility, Only for Spraying Fire, -30%; Armor Divisor (2), +50%; Cosmic, No Recoil Penalty, +50%; Increased Range, x50, +50%; Limited Use, 4/day, Fast Reload, -10%; Nuisance Effect, Only after the primary projectile hits, -10%; Rapid Fire, RoF 10, +100%) [150]

The device seems to be close to Portable (SM -2), so let us use it. For TL8 we get the cost of $590,000. To get the TL10 cost, we multiply it by x2.5 and get $1,475,000. Damn. That’s very close to vehicle mounted weapons.