I love mysteries. The fact of this being a mystery story therefore automatically gives it points in my book. Also, I have fond memories of those mystery stories aimed at kids: starting with Scooby Doo on TV, soon followed by the Encyclopedia Brown series, the McGurk mysteries, the Hardy Boys ... such fond memories. Bell Park doesn't take itself too seriously, choosing instead to poke fun at the implausibility of a child -- excuse me, a youth -- tackling a murder mystery.
As a mystery story, I'm not sure it really holds up to scrutiny. The clues, I think, are not really sufficient for the player to identify the murderer, and in fact the denouement does not appear to depend on who you actually finger when you are given the choice.
I would hesitate, however, in wondering why this wasn't written as static fiction. The fun here is in the gameplay itself, not in the unravelling of the mystery. Though all the branches converge back into the main storyline, there is just enough state tracking to give a touch of variety to the journey -- certain investigative options are only available depending on your previous choices. I would have liked a little more than what was available, but I enjoyed what I got.
This felt like a large bowl of Cocoa Puffs with milk: not huge on variety, but redolent of childhood Sunday afternoons spent curled up with an E.W. Hildick. Y'know, back before home computing became a thing.