Can you elaborate? I feel like this is the case with every game from this studio that I've played, unfortunately. I'm curious about 13 Sentinels but am worried I won't like it.
Will keep things spoiler-free, of course. I apologize for the vagueness, I agree that you should go in knowing as little as possible.
I unfortunately can't compare to other Vanillaware games, but I'd still recommend checking it out if you enjoy sci-fi thrillers. I found the process of going through the routes to uncover the truth really engrossing and as I mentioned, I loved the game once the truth was unfolding. The scale of what unfolds was very compelling and there are some really thrilling, exciting reveals and surprises throughout. That being said, the narrative has a lot of pacing issues. Each route will help you piece things together, but I definitely found some routes more interesting and productive than others. Some ended at odd spots, others missed opportunities and there's a little too much stalling than necessary. I wanted to spend more time exploring the truth than I wanted to stay at the surface and the game wouldn't let me. I was still able to enjoy a handful of characters quite a bit in spite of the narrative weaknesses and surprising inability to go beyond tropes, all things considered.
I think they could have reduced the amount of RTS waves, as you'll find yourself locked out of routes to go through battles at times and it can be frustrating to have to break away from the narrative puzzle you're solving. I felt a little bad at times since the RTS mode is fun, but I usually felt forced to do it. It also doesn't help that there is so much information to keep track of. You can look through the game's information to keep track, but needing an in-game wiki to keep track like this IS a flaw. I didn't exactly find the story that hard to follow, but I felt that it gave me too much info to sort through and be distracted by. The game IS aware of this and one character's route suffers from it greatly.
The game also struggles to develop important relationships for two reasons: first, the game seems to think that telling you that there is romance involved is enough, so many dynamics lack real chemistry and/or genuine development. Second, the game is more interested in making the female characters seem appealing to the audience by way of unfortunate tropes. I don't think that making characters appealing is automatically wrong, but if you don't really think very highly of your subject matter, then you won't really be able to represent its depth well. I've heard that the fanservice isn't as bad as it could be for Vanillaware and quite frankly, that's one low bar.
I've voiced my gripes, but I was still plenty motivated to see the game through and really powered through it on the strength of the mystery alone even if I don't think it wraps up that well.
