Blue Prince Board Game · Design Reference
Difficulty Curve Models
Comparing draft pool weighting strategies

The two models

Model A — Static Weighted Deck

One unified Active Bag (57 core room tiles). No rarity tiers — all rooms mixed together. Distribution is uniform. No deliberate escalation by rank.

Our current design. Simple to run. Slight natural drift as drafted tiles leave the pool, but uncontrolled.

Model B — Rank-Gated Progressive

Draw rules change by rank. Unusual and Rare rooms are locked out or heavily suppressed early. They escalate steeply toward Ranks 7–9. Players feel the manor getting harder and more unpredictable as they push north.

The VG approach. More faithful. Requires separate piles and rank-aware draw rules. More setup.

Probability of drawing Unusual or Rare (estimated)

Rank-Gated Progressive (VG model) Static Weighted Deck (our model)
RankStatic Weighted DeckRank-Gated ProgressiveDelta

Design notes

The static model is appropriate for prototype playtesting — it removes a variable so feedback isolates the core loop rather than difficulty tuning. If playtesting reveals that early and late ranks feel indistinguishable in tension, that is the signal to migrate to Model B.

Players familiar with the VG may notice the flattened curve at low ranks. New players may not. Whether this is a problem depends on the target audience and the playtesting pool.

Open question: After first playtest sessions, assess whether Rank 1–3 feels meaningfully different from Rank 7–9 in terms of drafting tension. If the answer is no, pivot to Model B using the rank-based draw rule structure that was the original design before the unified deck decision.

How to implement Model B (if needed)

Separate the active deck into four rarity piles at setup. Apply these draw rules by rank:

RanksSlot 1Slot 2Slot 3
1–4Active BagActive BagActive Bag
5–6Active BagActive BagActive Bag
7–8StandardUnusualUnusual
9UnusualUnusualRare

Unchosen tiles return to their rarity pile. Slot 1 gem cost always waived. Exhausted piles reshuffle their own discard.

Blue Prince Board Game Adaptation · Fan Project · Not for commercial use · April 03, 2026 · 04:56 UTC Mt. Holly · Room 46
Design Reference

Deck Composition & Probabilities

All card decks with quantities, percentages, and design rationale. Updated when deck contents change.

Common Items Deck — 30 cards

Drawn from room item spawns: Bedrooms, Green Rooms, Closet, Walk-in Closet, Attic. Represents items discovered randomly in rooms.

Card Qty % Design Note
Key620%Keys are the primary currency of movement — highest Common draw rate intentional
Gem620%Gems gate room access — equal weight to Keys
2 Coins413%Small coin drops supplement shop economy
3 Coins310%Larger coin drops rarer than small
Apple310%Most common fruit in VG — matches apple's frequency in source material
Ivory Dice27%Casino accessory — low frequency since Casino is optional Studio Addition
Banana27%Less common than Apple, matches VG rarity hierarchy
Empty (no find)310%Represents "high luck" required for random fruit/item in VG. Flag for playtesting — may need adjustment
Orange13%Rarest fruit in VG — single card reflects near-impossibility of random orange spawn

Special Items Deck — 24 cards

Drawn from specific rooms: Closet, Walk-in Closet, Attic, Toolshed, Trading Post, Mail Room. Higher-value items. Cards are instructions — the card tells you what to take from supply or the item card set.

Card Qty % Design Note
Salt Shaker211%Passive food modifier — 2 copies ensures reasonable chance of finding it
Magnifying Glass211%Gate code item — 2 copies so player can find it without needing specific room luck
Running Shoes211%Step boost — strong item, 2 copies feels right for early access
Ivory Dice211%Casino accessory — also appears in Common deck; two entry points
Locked Trunk token211%Spawns a trunk in current room — unexpected opportunity for keys/gems
Shovel312.5%One per run — single copy ensures scarcity
Sledgehammer312.5%Trunk bypass — powerful, appropriately rare
Metal Detector15%Doubles dig rewards — synergy item, single copy
Sleeping Mask15%Bedroom synergy — single copy
Lockpick Kit15%3-charge door bypass — also available at Locksmith for 6c
Treasure Map15%References Treasure Map deck — take one of the 8 fixed maps when drawn
Broken Lever15%Greenhouse lever path — also found via Dig Results
Cupcake15%+10 steps, consumed immediately. Only random source in base game
Coupon Book15%Shop discount — passive held item, single copy

Dig Result Deck — 21 cards

Drawn only when digging dirt pile tokens with the Shovel. Separate from item spawn decks.

Card Qty % Design Note
Nothing419%Digging always has risk — ~1 in 5 digs yields nothing
Key314%Most common useful find
Turnip (+6 steps)314%Consumed immediately — step recovery from digging
1 Coin210%Small coin find
Trash210%Junk — no effect. Combined with Nothing: ~29% chance of wasted dig
2 Coins15%Larger coin find
3 Coins15%Best coin find
4 Coins15%
Broken Lever15%Also in Special Items deck — two discovery paths
Secret Garden Key15%Rare dig reward — opens Secret Garden lever path
Silver Key15%Special Key from digging — lucky find
Metal Detector15%Found while digging — enhances future digs

Trunk Result Deck — 12 cards

Drawn when opening a locked trunk. Higher average value than Common Items — trunks should feel worthwhile to open.

Card Qty % Design Note
3 Gems325%Best gem haul in one action — rewards trunk investment
2 Keys217%Partially recoups key spent to open trunk
1 Gem + 1 Key + 2 Coins217%Mixed reward — always positive
3 Keys18%Best key return — nets 2 keys after trunk cost
2 Ivory Dice + 4 Coins18%Casino synergy reward
3 Coins18%Weakest trunk result — still positive. No trunk result is empty
Lockpick Kit18%Opens trunks without keys — recursive reward
1 Gem + Secret Garden Key18%Rarest trunk reward — unlocks Secret Garden lever path

Note: No trunk result is ever empty. Every trunk opened returns at minimum 3 Coins — always worth 1 key.

Playtesting flags Empty rate in Common Items (10%) — adjust if room item spawns feel too sparse or too generous. Dig Nothing + Trash rate (29%) — adjust if digging feels unrewarding. All percentages are starting points pending playtesting data.