Pretty Girls Rivers (Shisen-Sho) is a simple match two game. There are only a few rules. Matching pieces must be directly next to each other (no diagonals unless the adjacent tiles are empty). If the tiles are apart, and you were to draw a series of straight lines connecting them, the lines cannot bend more than two times.
It sounds a bit complicated but once you start playing, it’s very simple and intuitive for the most part. Picking a pair that cannot be connected will result in an error and you losing time to complete the level.
The game is fairly easy at first but as you progress it introduces new twists to mechanics to provide challenges. For example, some of the later levels have walls to prevent you from connecting pairs in a simple path. Some levels will actually have fail states if you match key pieces in incorrect pairings. Once you start playing, you start to see the patterns and get into a nice rhythm of clearing out obvious pairs and then working on the surrounding tiles.
As for the anime girls, it’s not really my thing but I’m sure someone will enjoy it. As with the Pretty Girls Breakout game, I’m not entirely sure how a normal human being will be able to focus on the game and still manage to look at the anime girls at the same time. It would require superhuman concentration and multitasking.
Overall, Pretty Girls Rivers is actually a decent match two game. It took me roughly around two hours to beat it. I did run into an unfortunate situation where the power ran out in my house on the last level and it corrupted my save file, making the save file unplayable. Looks like I’ll have to play through the whole thing again just to get the last achievement.