I'm basing this review on a first and blind playthrough of the Steam version of this game. (Matrix Hearts - Season 1, on 2013/10/07)
This first playthrough took me about 8 hours, though at least an hour of this was spent on taking notes, gathering my thoughts, and facepalming.
Link to the post detailing the errors, bugs and my general thoughts while playing the game.
Matrix Hearts starts with a gripping story. An Olympic hopeful suffers a sports injury, leading him into depression. He pushes away his friends, and finally his girlfriend. His parents decide to intervene and send him to a tropical island to rehabilitate. This rehabilitation is a state-of-the-art device, attached to his knee, that can transform hormones (good feelings) into magic healing power. Layla, our once-babysitter, now super-smart expert of this technology, is our caretaker and landlady on this journey.
While the setup of this game is original and solid, it almost immediately falls through. The writer(s) don't seem to understand what depression and introversion mean. When playing this game, you have to meta-game to find enjoyment. Just pick the "right" option, even if it goes against MC's nature. Any kind of role-playing will leave you confused about the MC's mental state and motivations.
The first two chapters of the game are relatively solid. There's somewhat of a story, and characters do seem to respect MC/player's choices. However, this all falls apart in the third chapter, where suddenly events pop up, even when they were avoided earlier. Out of the blue, my MC decided he had a planned meeting with Chrysta, and that he promised to go kayaking with Gemma. Suddenly, part of his day consisted of training in a lewd version of Magic: The Gathering, even if he told Dutch earlier (in a path-defining choice) that card games didn't interest him.
The choices, and dialog also makes clear that the devs just expect everyone to play for the lewds, and not the story. They pay lip-service to the MC being depressed and introverted, while making him a sardonic, wise-cracking jackass who chases all the women. His constant irony and self-deprecation is a constant throughout the game. While this kind of behavior is a tell-tale sign of depression, it isn't used as such, or to that effect. Everyone is constantly ribbing and bantering in the same way.
Many of the main characters speak alike, even if they grew up in different countries or have vastly different backgrounds. Everyone's a "bro", and even 40y/o's will say MC's knee is "borked". People don't talk this way.
The little animations I've seen were sub-par. There is clipping, janky movement, and loops that abruptly reset. Throughout my playthrough I encountered 4 missing renders.
The renders themselves are decent, even if a bit basic at times. Many of the poses are exaggerated and overused. The premise of the game gets lost in the renders as well, we'll see the MC climbing stairs without using the rails, or support his weight on his bad leg. We'll see him carrying people, squatting, crawling and running. Except when he can't, and he'll need someone's help to get up.
The Love Interests are varied enough to be interesting physically. I appreciate that there's variation, and that the smallest cup isn't an F. Even though they all speak alike, they do have their own character and interests. That said, some characters have very dubious motivations. An example of this is Layla, she asks Stormy to take MC on a date, because he could fix her "cum machine". Apparently she's unable to climax, and Layla thought it was a good idea to whore out the MC for this. This made my interest in Layla disappear. My MC was attracted to her, though it never escalated past flirting, at least there was some progression. Her whoring the MC out, I interpreted as her having zero interest in the MC.
Another example is Gemma, who, while knowing the MC can't swim, rocks the kayak to test his reaction. When he falls in the water, she berates him that "In every sport you have to operate under pressure! Ugh.". This is utterly irresponsible behavior, since she, as a quasi-professional had the job of preparing and training the MC for events like these. When she later asked if I wanted to join her team, the only reply I could bring myself to give was "I'll think about it." (Because the game didn't have the option to say "No, thanks, you're nuts, and I don't trust you with my life.")
The game lacks in other technical aspects as well. Readability in some scenes is very low due to the absence of a textbox. And even the main menu is unintuitive due to the angled gray text on a bright background.
On the top right of the screen is an icon representing the MC's knee device, when making choices a positive or negative score will display on it. However, I haven't found a way to get an overview of all Love Interests and their current scores. The most obvious way to do this, was to allow players to click the Matrix Hearts icon, sadly this doesn't work.
Matrix Hearts features 36 "otter pics" that can be found by finding and clicking an otter icon in certain scenes. It also has 20 lewd scenes.
Seeing as this is a steam release, I worry that most of these negatives won't get fixed. I can understand when one missing scene slips under the radar, when there are 4, I'm wondering if there's any QA done, or if the game was ever beta-tested. The steep drop in quality at the start of chapter 3 makes me even more worried about future chapters. The game seemed to transition to a pure kinetic experience, where choices don't really matter at all.