There are problems with the controls - I have found myself doing things I didn't mean to at points due to the vagueness sometimes, which is a shame. Using R2 to move has also worked out really badly. You're meant to use your head to look and R2 to move, and your character will turn when you've been looking for long enough, but because you need to walk along every wall and surface looking for action things you end up doing a lot of pointless stopping and turning around, which is aggravating.
There are also a few times where the game seems to lose its focus. Ideally, with interactive fiction (which Heavy Rain most certainly is), you want the player's interactions to be reflected in characters' relationships/thoughts/interactions with other characters, and affect the route of the plot, and in Heavy Rain, generally they do: you choose whether to forgive or reject someone, you can't find the clue in time, you manage to escape before you're killed, whatever it is - these depend on the player's morals, curiosity, or skill, and affect both the course of the narrative and the character you're playing (access your character's thoughts and they'll be reflecting on their previous actions, for instance). Particularly at the start of the game though, there's a ton of bagginess where you just fanny around with your kid, and it's in the name of character identification and connection to them. Now listen, Quantic Dream: I'll be identifying immediately with any character I'm playing, simply because I'm playing them, and this is proven by the fact that I cared as much about the three characters who have no backstories to the one who does. The backstory's useful for making sure you know about the guy's relationship with his kid, so that you care when the kid's kidnapped, but the game spends a ton of time getting there, and meanwhile, you're wandering around, looking at clocks, opening fridges, watching TV... it gets you nowhere. But that baggy stuff is really confined to the game's opening section and things get tauter as it progresses. When it comes to affecting the course of the plot, again, there are times at which you're just following a predefined set of actions where you literally can't change the plot, and that's disappointing. For instance, you play a flashback from years ago which only has one outcome, otherwise the entire plot would be different - so it feels pointless to play it, it might as well be a cutscene. Similarly, in the game's opening, you have to lose your son in a crowd, and so you're prevented from actually catching up to him by a thick crowd which, while heightening the drama, reduces the believability of the scenario; again, you're being cheated out of true interactivity here, so it feels like Quantic Dream are missing the point slightly. Those parts are a shame, but they're thankfully rare.
The set-pieces in Heavy Rain are terrific. Very exciting, particularly those which aren't standard fights (there are several of those) but which are more differentiated, such as a speedy drive down the wrong side of the motorway, and an attempt to negotiate cables which will electrify you if you touch them. The button prompts make sense and add to the tension of these sequences, whether it's because they arrive thick and fast or because you have to contort your body and use your nose to press them all at the same time.
The characterisation is good overall. Although you can see the archetypal platforms for most of them they're still well-written on the whole, so you've got your ex-cop-turned-private-investigator, junkie cop, dad-trying-to-save-and-reconnect-with-his-son, and such-and-such, and they all interact nicely and work well. The same goes for the plot, which blends dark intrigue with over-the-top elements, and again, I found it was well-judged, although there are occasions on which the dialogue is Avatar-bad. The game's tone is beautifully moody and rich, and there's just enough feeling of noir pastiche, particularly in Scott Shelby, the 30s-style private eye. The game's sets are fantastic as well, packed with incidental details and cars driving by the windows. It's a clich? to say they feel 'alive', but it's the best word that's coming to mind right now... perhaps 'solid' would be better? They just feel... real, I suppose.
The game's self-imposed 'maturity' generally works to its advantage, as you're experiencing a truly adult story with some genuinely horrific moments, moments which are shocking not for their graphic content but the ethical dilemmas it places you in. For instance, one character has to go through a series of Saw-style trials; the whole Saw thing about having to inflict pain and suffering upon yourself in order to survive? That idea shows its face in Heavy Rain, and when you're the person making the decisions, they're so much more terrifying. It helps that you care about the character enough to experience that terror and question your decisions, I think. There are points where it goes too far, though; the first time you meet the female character, you need to make her have a shower, and it's a shoddy excuse to look at her digitits and pretend it's not gratuitous. It just feels immature when that happens.