Shiny Colors, unlike most of the other iM@S games, is not a rhythm game. During auditions there is a mechanic that requires timing, but it's one press at a time and is generally rather easy. The majority of the gameplay revolves around managing the girls' time to grow their stats and abilities in a way that will let them pass the auditions. The game is far more about strategy (and RNG) than it is timing.

Pros

• The girls. There are currently 25 girls and they are all voiced and fleshed out. I would say Shiny Colors has the highest percentage of interesting idols. There are some that I'm indifferent on, but none get on my nerves.
• Story. This game is extremely story heavy. Every girl has multiple story arcs and new cards always come with at least two story scenes attached. Many of the stories focus on the sub-groups and not just the individual girls.
• Because many stories are attached to the cards, the game is very generous with currency for the gacha. It's also very easy to get the event cards and stories. Definitely not a grind for casual play.

Cons

• Shiny Colors has music and it's fine, but there's not much of it in the game, which is odd for an idol game.
• RNG sucks and can cause you to fail a run in some modes. There are ways to keep it under control when absolutely necessary, but it can still be frustrating.
• It's basically impossible to appreciate the game in any meaningful way unless you speak Japanese. There's no English version and there likely never will be.