Ryuki Belt Advent Deck is a free simulation game developed by RAINDAY STUDIO for Android devices. This game is designed for fans of the Kamen Rider series who want to experience the thrill of transforming into a Kamen Rider and battling monsters.

In this game, you can randomly draw a contract with a Mirror Monster and choose from 16 different decks and cards of Kamen Rider Ryuki. You can also customize your rider's appearance by selecting different belts, weapons, and armor. Once you have your deck ready, you can start battling Mirror Monsters and other Kamen Riders to earn rewards and upgrade your cards.

The graphics of the game are decent, and the sound effects and background music are well-suited to the game's theme. The gameplay is relatively simple and easy to understand, making it accessible to both new and experienced players. Overall, Ryuki Belt Advent Deck is a fun and engaging game for Kamen Rider fans who want to experience the excitement of being a Kamen Rider.