How an original slot game is made: from GDD to release

This is also the pipeline behind our slot game development services — studios and platforms can commission the full process or any single stage of it.

Every original slot game at Giro Games goes through the same four-step pipeline — and understanding it explains why in-house production beats white-label catalogues for quality.

1. Concept and game design document

A slot starts as a theme worth building around: a character, a world, a mechanic. The GDD fixes the reel layout, feature set, bonus structure and target audience before a single asset is drawn.

2. Math and simulation

RTP, volatility and hit rate are designed as a system, then proven across millions of simulated spins. Our released games ship with RTP between 96.05% and 97.00% — numbers we can defend spin by spin.

3. Art, UI and animation

In-house artists build symbols, backgrounds, UI and transitions as one visual language, optimised for HTML5 and mobile play.

4. Development, release and updates

The game is engineered, tested, certified and released with casino partners — then tuned and updated after launch. That is the difference between shipping a slot and maintaining one.

Read next: Behind Midas Golden Era: our flagship slot · How to choose a slot game provider

What should be ready at each hand-off?

A useful way to review the process is to ask what the next specialist needs to receive. The concept stage should leave a readable description of the base game, feature triggers and player-facing rules. A maths hand-off should identify the configuration being tested, so a change to a feature cannot quietly leave the written rules behind.

For art and animation, review a complete reel-sized symbol set rather than isolated large illustrations. Check normal, highlighted and winning states together, then agree on export sizes and file names before integration. The same approach applies to sound: each cue needs a clear event, duration and behaviour when it overlaps another cue.

Before release, compare the playable build with the approved document and keep a list of changes. That gives the studio and its partner a shared reference for acceptance, bug reports and later updates. Our Midas Golden Era case study shows how one theme carries across several of these disciplines.