Primal Hearts is a game I have an odd relationship with. At the time I first played it, I don't think I gave it a completely fair assessment. The reason why? I was hitting the first of my many 'charage doldrums' periods. However, in retrospect, it grew on me... sort of like mold.
First, I should note that the game is actually fairly old-fashioned, despite its modern visuals. The wacky concept, larger-than-life characters, and the sometimes ridiculous 'coincidences' that pop in all hearken to a previous era. At various times, this game channels such famous games as Haruka ni Aogi, Uruwashi no, Majikoi, Shuffle, and any number of 'golden age' games. Of course, it doesn't go as far as any of those does, but the makers' fanboyism is fairly evident throughout the game on a second playthrough (something I didn't notice on the first playthrough).
First, the resemblance of Majikoi lies in the larger than life characters and sometimes crazy abilities some of them have (the protagonist included). The protagonist's casual manipulation of the other characters for his own amusement (and for their own sakes, more often than not) is very much reminiscent of Yamato, without ever actually approaching his level.
Perhaps the strongest resemblance to Haruka ni Aogi, Uruwashi no lies in Haruhi's path... to be blunt, Haruhi is a redesigned version of Miyabi, with Kanna a reformed version of Lida who also happens to be a heroine. The resemblances and relationships are so obviously drawn from fanboyism of that particular kamige that I just had to shake my head during this replay.
Shuffle is channeled, along with a lot of other early charage, through the setting. While the specifics are drastically different, the wacky, overblown occurrences, the general madness surrounding the 'elections', and any number of other factors in the setting make me nostalgic for the middle of last decade (soon to be the decade before last).
I perhaps didn't notice all this the last time because I was focused on heroines... and I was playing charage rather mechanically already, two years into VN of the Month. A peculiar element that you generally don't see in most charage in general is character designs like that of Mizanori. Most charage tend to make all their regular characters (the ones at the center of the cast) attractive to one degree or another. However, Mizanori stands out as a character who was made comically unattractive, which struck me as hilarious at the time, since I used to make some of the same excuses he did to eat more as a teenager, lol.
The common route of this game is excellent. The relationships between the characters are formed and deepened appropriately, and it actually makes sense that the heroines would fall for the protagonist by the end. It helps that the protagonist is really a 'great guy' in every way, though he can lack common sense at times. The decision to avoid mediocrity in the protagonist and those around him is one that is rarely made in charage, which just made it that much better as a result.
Sadly, after the common route, this game stumbles somewhat. The heroine routes lack some of the depth the common route does, perhaps because the shift to romance automatically debuffed the intelligence of the writers. Oh, the heroines are unbearably cute when they go dere (Sera's dere makes me giggle hysterically even now, and Haruhi's is as strong in its own way), but the 'drama' included in the heroine paths pales a great deal in comparison to the drama that pops up in the common route. In that sense, it felt almost like they were running out of ideas at the end...
Overall, this is an excellent charage that manages to escape mediocrity by channeling some of the best parts of a number of famous VNs into its characters and setting. I won't say it is a kamige (because it isn't), but if you are just looking for a good charage to add to your collection, this is a good choice.