H7
Tourist
Top premium pay symbol
- 5×40× bet$40.00
- 4×16× bet$16.00
- 3×6.5× bet$6.50
Featured Software · 2026
Lost Island
A production jungle adventure casino slot — full math engine, Svelte/PixiJS client, free spins, coin Hold & Spin, expanding wilds, and jackpot tiers. Built under contract, taken through Stake Engine's full approval process, and now live on the platform.
Live on
Platform Status
Approved & Live on Stake.us
Lost Island went through Stake Engine's full approval pipeline — three independent reviewers, a math audit against the published books, RGS and replay integration testing, and jurisdiction plus Social-mode compliance — and is now published on the platform.
Approval Snapshot
- Approved and published on Stake.us — rating process closed as complete
- Rated 2-Star on Stake Engine's quality scale by three independent reviewers
- Live front-end build: v1.1.0 (29 Jul 2026)
- Live math build: six-mode publish pack (29 Jul 2026)
- All six bet modes returned COMPLIANT on the published-books audit
- Cleared Stake's full approval checklist — RGS integration, replay, jurisdiction and Social-mode wording
What Shipping Actually Took
Approval is not a formality. Across three review rounds the build was reworked to drive every monetary value dynamically off the RGS authenticate response for all currencies, hold exact decimal precision on wins and in the info screens, hard-fail on a tampered RGS URL, emit correct replay events, and scrub all restricted terminology from Social mode.
Each round was closed by re-publishing the front-end and math builds through Stake's own versioning — 35 front-end revisions and 5 math revisions between submission and go-live.
Interactive Game Info
Paytable · Lines · Bonus Buy
Live-style controls for the shipping 5 reels × 4 rows · 12 fixed paylines model — production math from the shipping game_config (12 lines, 40-credit bet unit). Change total bet to see cash pays and all five bonus-buy costs scale live.
Total Bet12 lines · 40 credits = 1×
$1.00
MINI$20.0020× bet
MINOR$100.00100× bet
MAJOR$500.00500× bet
GRAND$5,000.005000× bet
Paying Symbols
H6
Explorer
Premium character
- 5×25× bet$25.00
- 4×10× bet$10.00
- 3×5× bet$5.00
H1
Crocodile
High-pay animal
- 5×15× bet$15.00
- 4×6× bet$6.00
- 3×3× bet$3.00
H4
Orange Frog
High-pay frog
- 5×12× bet$12.00
- 4×5× bet$5.00
- 3×2.5× bet$2.50
H5
Green Frog
Premium — appears during Free Spins only
Free game only- 5×10× bet$10.00
- 4×4× bet$4.00
- 3×2× bet$2.00
H2
Tarantula
High-pay arachnid
- 5×6× bet$6.00
- 4×3× bet$3.00
- 3×1.5× bet$1.50
H3
Spider
High-pay spider
- 5×5× bet$5.00
- 4×2.5× bet$2.50
- 3×1× bet$1.00
L1
A
Top low royal
- 5×1.8× bet$1.80
- 4×0.9× bet$0.90
- 3×0.4× bet$0.40
L2
K
Low royal
- 5×1.6× bet$1.60
- 4×0.8× bet$0.80
- 3×0.3× bet$0.30
L3
Q
Low royal
- 5×1.4× bet$1.40
- 4×0.7× bet$0.70
- 3×0.2× bet$0.20
L4
J
Low royal
- 5×1.2× bet$1.20
- 4×0.6× bet$0.60
- 3×0.2× bet$0.20
L5
Rope
Low object · the floor of the ladder
- 5×1× bet$1.00
- 4×0.5× bet$0.50
- 3×0.1× bet$0.10
Specials
W
Wild
Substitutes for all pay symbols · carries 1×–500× during Free Spins · multiplied wilds (2×+) on a line add together · line pays match H1
- 5×15× bet$15.00
- 4×6× bet$6.00
- 3×3× bet$3.00
W
Purple Wild
The Wild's multiplied face — shown whenever it carries 2× or higher (up to 300× on Xtra Wilds reels)
25X shown as an example — rolled per landing- 5×15× bet$15.00
- 4×6× bet$6.00
- 3×3× bet$3.00
WG
Gold Wild
Expanding wild covering the entire reel · multiplier rolls 1×–250× via the carousel reveal · sticky for the rest of the feature · counts once per reel
50X shown as an example — rolled per landing- 5×15× bet$15.00
- 4×6× bet$6.00
- 3×3× bet$3.00
S
Bonus
Volcano scatter · 3 / 4 / 5 → 8 / 12 / 15 Free Spins · 2+ during Free Spins retrigger 1 extra spin per scatter
Feature symbol · no line pay
C
Coin
6+ coins trigger Hold & Spin · carries a cash value or a MINI–GRAND jackpot tier
Feature symbol · no line pay
XW
Xtra Wilds
Trigger symbol — lands with exactly 2 Bonus symbols to enter Bonus + Xtra Wilds (8 Free Spins on wild-rich reels). Never pays a line itself.
Feature symbol · no line payTiki Coin Faces
Inside Bonus + Xtra Wilds the Tiki Coin wears one of four faces depending on the multiplier it carries. Every collected coin adds into an on-screen Global Multiplier — up to ×250 — that multiplies every win for the rest of the feature.
Win Celebrations
Every Win Tier, In Motion
The four win-celebration sprite sheets the client plays live — Big, Mega, Super, and Ultra — triggered off the same win-tier thresholds used in production.
Big Win
Mega Win
Super Win
Ultra Win
96%Certified RTP · all 6 live modes
12Fixed paylines · 5×4 board
25,000×Max win · verified reachable
4Jackpot tiers · coin respin
Project Overview
What We Built
Lost Island is a production-grade 5×4, 12-line casino slot built under contract with Rush Social Game Studios for Stake Engine distribution — and it is now approved and live on Stake.us. Scott Applications delivered the full game stack: a certified 96% RTP math model (Python/Stake Engine SDK with free-game and coin Hold & Spin features), a high-performance Svelte + PixiJS web client with polished desktop landscape and mobile portrait HUDs, tiki jackpot pillars, expanding wilds, free spins (8/12/15) with retriggers, coin respins with MINI/MINOR/MAJOR/GRAND jackpot tiers, max-win celebration, and operator-ready compliance polish. It then cleared Stake Engine's full approval pipeline: a math audit that returned COMPLIANT on all six bet modes at 96.0000% RTP with the advertised 25,000× max win verified reachable, plus three rounds of platform review covering RGS integration, replay fidelity, multi-currency handling, and jurisdiction and Social-mode compliance. Shipped as a complete frontend + math package — from loading screen art, in-game info pages, and symbol set through live spin UI.
iGamingSveltePixiJSPython MathStake EngineTypeScript
Visuals
Live Previews & Production Art
Desktop landscape, mobile portrait, max-win celebration, reel frames for every game mode, backgrounds, the coin Hold & Spin banner, jackpot board, and loading art — production UI straight from the shipping client.
Math Engine
RTP, Volatility & Feature Economics
Math was treated as a hard constraint — not a post-art guess. Monte-Carlo simulation seeded the production optimizer against Stake Engine's 2-Star envelope, and the whole pack has been re-simulated and re-optimised end to end since launch rather than patched. Every figure below is measured from the books that are live on the platform, and all six modes returned COMPLIANT on the current published-books audit.
Certification Snapshot
| Metric | Target | Validated | Status |
|---|---|---|---|
| Total RTP | 96.0% | 96.0000% across all 6 published modes | Pass |
| Base-game volatility | Stake limit < 50 | 20.12 · 2-Star envelope | Pass |
| Max win / wincap | ≤ 25,000× | 25,000× reachable · 1 in 18,760 (Bonus + Xtra Wilds) | Pass |
| Paylines | 12 fixed | 5×4 board · L→R lines (was 40) | Pass |
| Hit rate (base) | 5% – 33% | 29.85% · zero-payout rate 70.15% | Pass |
| Payout spread | ≥ 10 unique | 34,143 distinct payout values · no gaps | Pass |
| Free-spin trigger | — | 1 in 306 · 1 in 1,209 · 1 in 2,252 (3/4/5 Bonus) | — |
| Xtra Wilds trigger | — | 1 in 1,420 | — |
| Coin Hold & Spin trigger | — | 1 in 185 | — |
Board & Rules
- Board: 5 reels × 4 rows · 12 fixed paylines (updated from 40)
- Bet unit: 40 credits = 1× total bet (engine anchor after 12-line port)
- Wild multipliers on a winning line are SUMMED (not multiplied)
- Free spins: 3/4/5 Bonus symbols → 8 / 12 / 15 spins · 2+ retrigger 1 spin per scatter
- Coin Hold & Spin: 3 respins, reset on each new coin (6+ coins)
- Jackpot tiers (× bet): MINI 20× · MINOR 100× · MAJOR 500× · GRAND 5,000×
- Xtra Wilds + exactly 2 Bonus symbols → 8 free spins on wild-rich reels
- Graded low ladder: A > K > Q > J > Rope each pay a distinct step (2026-07-29)
- Player-facing volatility: Extreme, 5 of 5 — on all six modes
Game Features
What Players Feel
Three feature pillars — free spins, coin respins, and expanding wilds — each wired through math modes and the live client.
Free Spins
Land 3–5 Bonus symbols for 8 / 12 / 15 free spins, and 2+ landing during the feature retrigger one extra spin per scatter. Free-game reels run hotter wilds carrying 1×–500× multipliers. The H5 green frog pays in the free game only.
Coin Hold & Spin
Six or more coins on a base spin starts Hold & Spin: 3 respins that reset every time a new coin lands. Coins lock cash values or MINI / MINOR / MAJOR / GRAND jackpot tiers, with GRAND paying 5,000× bet — the mode's own cap.
Bonus + Xtra Wilds
The Xtra Wilds symbol landing with exactly 2 Bonus symbols opens 8 free spins on wild-rich reels. Purple Wilds carry up to 300× and the sticky Gold Wild up to 250×. Tiki Coins land carrying multipliers that feed an on-screen Global Multiplier — it starts at 1× and climbs to ×250 — applied to every win for the rest of the feature. The 200× buy runs the exact same board it advertises.
Expanding Wilds
The Gold Wild covers an entire reel, rolls a 1×–250× multiplier through a carousel reveal, and stays sticky for the rest of the feature. Multiplied wilds (2×+) on a winning line are summed rather than multiplied — a design detail that shapes both feel and RTP tuning.
Delivery Stack
Frontend, math, and platform contracts owned as one system so spin books and UI state stay aligned from simulator to live play.
SveltePixiJSTypeScriptPythonStake Engine SDKMonte-Carlo SimMobile HUDBonus Buy
Contracted Studio Partner
Rush Social LLC
Lost Island was engineered under contract with Rush Social Game Studios — studio IP and art direction paired with Scott Applications' math, client, and compliance engineering for Stake Engine distribution.
Visit Rush (opens in a new tab)Our Stack
Technologies Behind Lost Island
Math, client, and platform tooling treated as one shipping system — not three disconnected freelancers.
Game Client
Svelte + PixiJS
TypeScript
Mobile HUD
Bonus Buy / Features
Math & Platform
Python Math SDK
Monte-Carlo Sim
Stake Engine
2-Star Envelope
Delivery
Git Workflows
Tooling / RGS
iGaming Features
Full-Stack Ownership