If you've played Silent Hill 1 and 2, how similar is this to them?
It isn't similar at all. There are significantly less enemies and you are safe as you roam around the city.
You essentially travel from one crime scene to another, fight a few monsters and search for clues. Sometimes you need to visit one of the information hubs (police station, hospital, newspaper) to research clues as well.
The atmosphere is good and the story seems to be strong enough one third of the way in, but I have only seen 3 or 4 types of enemies so far and the game flow, as I have seen a lot of reviewers note, stays very similar through each case.
Also, the city streets are very uninteresting. The same four or five character models shuffle around doing the same sorts of things over and over. Most buildings are inaccessible and there really just isn't a whole lot going on for what is apparently considered an "open world" game.
Oh, and the motorboat controls are unpleasant. Unfortunately you need to use it quite a bit.
The detectiv-ing parts are still the best aspect even if they are pretty straightforward, as well as the creepy ambience (especially for a Lovecraft fan).
Definitely worth 9 or 10 dollars for an amalgamation of ps1-era survival horror and LA Noirey (etc) detective work.