Every spin outcome is decided on the server with a cryptographically secure RNG and a fixed, auditable paytable. The browser only animates the result. Below you can play, read the rules, and run your own simulation to verify the published RTP.
The published RTP is not a promise, it is a measurement. Press the button and the server plays hundreds of thousands of spins with the exact same engine the game uses, then reports what came back. Numbers move slightly between runs: that is variance, not tuning.