Creative case study
Engineering the high-stakes bonus round system for a live slot title — including a pick-em feature, a free-spin multiplier trail, and a wheel-of-fortune overlay, all driven by a reusable state machine.
Client
European Slots Studio
Role
Senior Game Developer
Year
2026
Discipline
HTML5 Game Development
Doodle concept visualBonus round engagement time increased by 3× compared to the studio's previous simple free-spin implementation.
The hero image is loaded from the MDX coverImage field. Replace the demo URL with your own gameplay capture, PixiJS canvas screenshot, or rendered artwork.
3 distinct modes
Bonus types
3× session time
Engagement uplift
XState machines
Reusable states
The client's existing slot game had a simple free-spin bonus — the reels just spun 10 times for free. Player retention during bonus rounds was low, and the studio wanted something memorable and share-worthy.
I designed and built three distinct bonus systems, each sharable via the base game's trigger system:
A 3×3 grid of mystery items. Players click to reveal prizes — coin values, multipliers, or a "collect" symbol that ends the round. Built entirely in PixiJS with InteractionManager events. Items use Spine animations for idle shimmer, select, and reveal states.
A 5-stop trail displayed above the reels. Each free spin advances the player one step along the trail, increasing a persistent multiplier. The trail is a custom PIXI.Graphics path with animated fill using a masked gradient sprite.
A full-canvas spinning wheel overlay triggered as a super bonus. The wheel uses a physics-inspired deceleration curve driven by GSAP. The winning segment is determined server-side before the spin starts — the GSAP target rotation is calculated to land exactly on that segment.
All three bonus modes share a single BonusStateMachine built with XState. States include: INTRO, PLAYER_TURN, AWAITING_SERVER, REVEAL, ADVANCE, OUTRO. This eliminated the nested if/else logic that plagued the previous implementation and made adding new bonus types trivial.
Average session length during the bonus round increased from 45 seconds to over 2 minutes. Social sharing of big-win screenshots increased noticeably within the first month of release.
More Case Studies
A technical deep-dive into how production iGaming studios store, version, and serve complex game math configurations across operators, jurisdictions, and variants.
A complete blueprint of an enterprise iGaming backend system: from the Seven-Layer Model and 48ms game transaction loops to GLI compliance and scaling pipelines.
An educational compiler project translating academic Computer Science theory into a working plain-English general-purpose compiler that compiles directly to zero-overhead x64 assembly.
