(Note: this is more of a review of the entire series.)

9-nine- is a popular visual novel that's a blend of action, mystery, and supernatural genres. This isn't something I normally read (I mainly read slice-of-life), so I don't have anything to compare to, but in a vacuum, it's pretty solid.

Pros:

The mystery and supernatural element- The mechanics are explained clearly and in detail, and everything was slowly revealed, making it easy to understand and follow along. This made me much more invested in the story and thinking about everything that happens.

The characters- I often get more invested in the characters than the actual story. Every heroine gets their moments to shine, especially in their own episode. I enjoyed getting to know the characters, and watching them interact with each other. This extends to the protagonist Kakeru as well. He has a clearly defined personality, so he really stands out among a sea of generic VN protagonists. Him being voiced further emphasizes that he's his own character.

The action- You can't have an action story without the fight scenes, and for the most part, they do their job well. Even as someone that struggles with attention span, during the most climactic moments, I can usually read through the entire fight scene (which can last an hour or even longer) in one sitting.

Cons:

Romance- Yes, I know romance isn't the main point of this series. But the romance often felt awkward because it's shoehorned in and separate from the main plot.

Pacing- The pacing sometimes felt weird, alternating between long stretches with nothing really happening, and then suddenly too much happening at once.

Pricing- This easily could have been a single VN, but instead, it's divided into five episodes, and the cost adds up. The entire series costs 90 USD, and even getting it at a steep discount set me back 33 USD. And if you're thinking about buying the first episode to test the waters, that's not a good idea, as it isn't really representative of what the later episodes are like. You really just have to take a risk and buy this entire series at once.