4.8 KiB
Vertical Slice Report: [Concept Name]
Date: [YYYY-MM-DD] Slice Duration: [N days] Target Scope: 3–5 minutes of polished, continuous gameplay Source GDD: design/gdd/game-concept.md
Validation Question
[The full game loop question this build was proving — both experience AND feasibility: "Does a player, starting from nothing, experience [core fantasy] within [N] minutes, without developer guidance — and can we build one such loop in [X] days at representative quality?"]
Scope Built
[Systems implemented, art quality level, what was intentionally omitted.]
Systems included:
- [System 1]
- [System 2]
- [...]
Art/audio quality level: [Placeholder / Representative / Near-shipping] Shortcuts taken deliberately: [List] What was cut from original scope: [List]
Build Velocity Log
[Day-by-day record of what was completed. This is your real production rate data — use it in sprint planning.]
| Day | Completed |
|---|---|
| Day 1 | [What was built] |
| Day 2 | [What was built] |
| Day 3 | [What was built] |
| ... | ... |
Total elapsed: [N days] for [scope summary] Velocity estimate: [N hours per equivalent scope unit — e.g., "1 day per combat encounter, 0.5 days per UI screen"]
Playtest Results
| Attribute | Value |
|---|---|
| Total sessions | [N] |
| Internal testers | [N] |
| External testers | [N — people who had not seen the game, if available] |
| Avg session length | [N minutes (target: [N] minutes)] |
| Time to first meaningful action | [N seconds (target: [N] seconds)] |
Observations
[Specific, non-opinion observations from playtest sessions. Quote testers where useful.]
Where testers succeeded without guidance:
- [...]
Where testers were confused or stuck:
- [...]
Emotional reactions observed:
- [...]
Metrics
| Metric | Target | Actual |
|---|---|---|
| Time to first meaningful action | [N sec] | [N sec] |
| Session length | [N min] | [N min] |
| Critical fun blockers found | 0 | [N] |
| Pipeline blockers found | 0 | [N] |
| Architecture surprises | 0 | [N] |
Feel assessment: [Specific — "combat feedback weak; no impact sound on hit" not "felt rough"]
Recommendation: [PROCEED / PIVOT / KILL]
[One paragraph with evidence — reference the validation question directly. Did a player experience the core fantasy within the target time, without developer guidance? Can the team build at this quality on the projected schedule?]
If Proceeding
Production requirements (what must change from slice to production):
- [e.g., "Replace placeholder art with shipped assets"]
- [e.g., "Combat system needs 2 more weapon types"]
Architecture adjustments needed:
- [ADR to update or create]
Sprint velocity estimate based on slice data:
- [e.g., "1 day per enemy type, 2 days per level section, 0.5 days per UI screen"]
Scope adjustments from original design:
- [What the slice revealed about the true production scope]
Performance targets: [Confirmed / Revised — list changes if revised]
Playtest note: Run /playtest-report to structure additional session data
before running /gate-check pre-production.
Next steps:
/gate-check pre-production— formally advance to Production/create-epics layer:foundation— plan Foundation layer epics/create-epics layer:core— plan Core layer epics/sprint-plan— use velocity data from this report in the estimate
If Pivoting
[Which GDDs need revision and why — be specific about the failure mode observed.]
Systems requiring GDD revision: [List]
Architecture decisions to revisit: [List — use /architecture-decision to update]
Core loop change needed: [What specifically to change]
Next steps:
/design-system [mechanic]— revise affected GDDs/architecture-decision [decision]— address architecture issues/vertical-slice— re-validate after revisions
If Killing
[Why the full game loop does not work at this quality level. What specifically prevented the player from experiencing the core fantasy. What to do instead.]
Next step: /brainstorm to explore a new direction, or /prototype [new-concept]
to test a different concept cheaply before investing in another vertical slice.
Lessons Learned
-
What assumptions were broken by building to near-production quality? [...]
-
What surprised us about the pipeline or architecture? [...]
-
What would we change about the slice scope if we ran this again? [...]
Vertical slice code location:
prototypes/[concept-name]-vertical-slice/This code is reference material only. Production implementation is written from scratch. Never import or refactor this code into production.