PHYSICS-FORTRESS BATTLE (CHARGE! Edition) — Portfolio GDD

One-line Hook

A fast competitive artillery game where players earn hits by doing projectile math, then choose whether to push their luck for bonus damage with CHARGE!.

Elevator Pitch

PHYSICS-FORTRESS BATTLE turns core kinematics into a tight tabletop duel: players draw an attack (m, v₀), choose an angle, compute range to match a declared target band, then convert kinetic energy into damage. Dice add bounded uncertainty (launch reliability + drift), and CHARGE! creates a high-agency push-your-luck layer that rewards confidence while preserving tension. It is designed for quick play, clear state visibility, and classroom deployment without sacrificing competitive depth.

Genre / Player Count / Session

• Competitive tabletop / educational tactics
• 2–4 players
• 10–25 minutes (scales with player count and Integrity tuning)

Design Pillars (What the game is “about”)

1. Skill Gate Before Chance
   Math happens first. Players must earn the roll by hitting a range band.
2. Bounded Uncertainty, Not Random Outcomes
   Dice cannot create damage from a miss; they only modulate a successful solution.
3. Agency Under Risk
   CHARGE! is optional and player-controlled: “bank” value vs “bust” volatility.
4. Readable Combat State
   Integrity boxes make damage, breach, and elimination instantly legible.

Core Experience Loop (Player-facing)

Draw → Declare (side + angle) → Compute R → HIT? → Compute KE → Launch Roll → Drift (sometimes) → Base Damage → Optional CHARGE! → Breach/Eliminate check → Next player

Moment-to-moment decisions

• Which side band to target (risk/reward, finish opportunities, defense reading)
• Which angle to use (accuracy vs drift profile at 60°)
• Whether to CHARGE! and how long to press (STOP vs BUST)

Target Audience & Use Cases

• Primary: students learning projectile motion + energy, competitive learners, game-based learning environments.
• Secondary: casual tabletop players who enjoy quick tactical duels and push-your-luck.
• Classroom modes: team-vs-team, stations, warm-up competition, review day.

Core Systems (Cohesive Summary)

Components

• Fortress board per player with 4 sides (W/S/E/N), each at Integrity 6 (□□□□□□).
• Attack deck: each card shows m (kg) and v₀ (m/s).
• Dice: d6 and 3d6.

Target Bands (Range Targets)

Declared side determines band:

• W: 10 m, S: 16 m, E: 20 m, N: 22 m
  HIT if |R − band| ≤ 1.5 m.

Physics-First Resolution (always before dice)

• Range: R = v₀² · Fθ, θ ∈ {30°, 45°, 60°}
  F30 = 0.0884, F45 = 0.102, F60 = 0.0884
• Kinetic Energy: KE = 0.5 · m · v₀²

Launch Reliability: ARTILLERY-11

Roll 3d6 after math:

• 11 MISFIRE (no damage, no CHARGE!)
• ≤11 launches
• ≤5 PERFECT RELEASE (launches, skip drift)

Air Drag (drift affects side only, not R)

Only if: HIT + launched + not Perfect Release.
CW: N→E→S→W→N; CCW: N→W→S→E→N
Drag die: 1–2 CCW, 3–4 none, 5–6 CW

• θ 30°/45°: 1 die
• θ 60°: 2 dice combine to a single drift (never drift 2 sides)

Damage Conversion (base damage to final side)

• KE ≥ 30 J → 3 boxes
• 20–29.9 J → 2
• 10–19.9 J → 1
• < 10 J → 0
  Integrity floors at 0.

CHARGE! (Signature Mechanic / Differentiator)

Design Intent

Convert “I solved it” into a meaningful gamble: extra damage is not random—risk is chosen.

Trigger

CHARGE! may be declared only after a Successful Shot: HIT + launched (3d6 ≤ 11). Perfect Release counts.

Procedure (always 3 dice per pull)

Each pull is 3d6:

• 1=W, 2=S, 3=E, 4=N → bank +1 damage to that side
• 5 → no effect
• 6 → lock as Danger (set aside), then replace so next pull is always 3 dice

Stop anytime:

• If you STOP before 3 total locked 6s: apply banked damage to the indicated sides.
• On the 3rd locked 6: BUST immediately (lose all CHARGE! banked damage).

Why it works

• Rewards situational awareness (finish a breached fortress, spread damage, or snipe weak sides)
• Provides tension without undermining the math-first identity

Fortress States (Breach & Elimination)

• Breach: any side hits 0 → fortress becomes BREACHED (still plays)
• Elimination: a BREACHED fortress is eliminated the next time it takes ≥1 damage (base or CHARGE!)

Design intent: “One more shot” creates drama, comeback windows, and clear finish pressure.

What Makes This Portfolio-Worthy (Explicit Claims)

1) Strong Skill/Chance Architecture

• MISS ends the turn before any roll: avoids “dice doing the work.”
• Dice modulate success (launch + drift), not replace it.

2) Clean Risk Layering

• Base damage is deterministic from KE tiers.
• CHARGE! is optional volatility with a strict bust condition.

3) High Readability + Fast Teaching

• Integrity boxes are a visible scoreboard.
• Angle set is constrained (30/45/60) and trig is removed via Fθ constants.

4) Tunable for Classroom or Competitive Play

You can tune difficulty, length, chaos, and learning load without rewriting the engine.

Balancing & Tuning Knobs (with expected outcomes)

• HIT window (±1.5 m): tighter = more skill, shorter CHARGE frequency.
• Band distances (10/16/20/22): rebalances side value and “best θ” patterns.
• Artillery threshold (11) & Perfect Release (5): controls reliability and drift frequency.
• Drag distribution and 60° combine rule: controls variance and “angle personality.”
• KE damage tiers: main time-to-kill lever.
• CHARGE bust at 3 locked 6s: adjusts aggression and average bonus damage.

UX / Rules Clarity (Anti-Lawyering Definitions)

• Declared side: side chosen before math.
• Final side: side after drift (if any).
• Successful Shot: HIT + launched (3d6 ≤ 11).
• Perfect Release: 3d6 ≤ 5; skip drift.
• Air Drag changes only side, not computed R.
• CHARGE! bank damage may hit multiple sides; base damage hits only final side.

Appendix A — Worked Example Turn (Complete)

Setup Assumptions

Target bands: W 10, S 16, E 20, N 22. HIT window ±1.5 m.

Example Attack Card

m = 0.20 kg, v₀ = 14 m/s

Step 1: Declare

Player declares target side E (20 m) and angle 45°.

Step 2: Range

R = v₀² · F45 = (14²) · 0.102
14² = 196
R = 196 · 0.102 = 19.992 m ≈ 20.0 m
Check HIT: |20.0 − 20| = 0.0 ≤ 1.5 → HIT

Step 3: KE

KE = 0.5 · m · v₀² = 0.5 · 0.20 · 196
0.5 · 0.20 = 0.10
KE = 0.10 · 196 = 19.6 J

Base damage tier: 10–19.9 J → 1 box

Step 4: Artillery-11

Roll 3d6 = 9 → ≤ 11 launches (not Perfect Release)

Step 5: Air Drag (45° uses 1d6)

Roll d6 = 6 → drift CW one side
CW from E → S
Final side becomes S

Step 6: Apply Base Damage

Apply 1 box to S integrity of the defender.

Step 7: Optional CHARGE!

Player declares CHARGE! (allowed: Successful Shot).

Pull 1 (3d6): 1, 4, 6

• 1 → W-bank +1
• 4 → N-bank +1
• 6 → lock Danger (Danger=1), replace next pull to keep 3 dice

Player chooses to press.

Pull 2 (3d6): 2, 5, 6

• 2 → S-bank +1
• 5 → none
• 6 → lock Danger (Danger=2)

Player chooses to STOP (Danger < 3).
Apply CHARGE! banked boxes: W +1, N +1, S +1 to the defender after base damage.

Net result this turn

• Base: S takes 1
• CHARGE!: W takes 1, N takes 1, S takes 1
  Total: 3 bonus-distributed boxes + 1 base box across sides.

Appendix B — Edge Case Examples (Quick)

B1) MISS Example

Declared N (22 m), computed R = 19.0 m → |19−22|=3.0 >1.5 → MISS
Turn ends immediately: no roll, no damage, no CHARGE!

B2) MISFIRE Example

HIT achieved, KE computed, Artillery roll = 12 → MISFIRE
No damage, no drift, no CHARGE!. Turn ends.

B3) Perfect Release Example

HIT achieved, Artillery roll = 5 → Perfect Release
Skip drift. Damage applies to declared side (final side = declared side).

B4) 60° Drift Combine Example

At θ=60°, roll 2d6:

• If 1 (CCW) and 6 (CW) → cancel (no drift)
• If 1 (CCW) and 2 (CCW) → drift CCW 1
• If 3 (none) and 6 (CW) → ignore none, drift CW 1
  Never drift 2.

Portfolio Presentation Notes (How to show this on a site)

Include these artifacts as separate sections:

1. One-page Pitch Sheet (Hook, Pillars, Loop, Differentiators)
2. Rules Overview (the core engine in ~1 page)
3. CHARGE! Deep Dive (why it exists, how it plays)
4. Worked Example (Appendix A)
5. Tuning Knobs + Playtest Notes (even if brief)