The overall score in this review is (clearly) heavily influenced by my fangirl heart, beating to the rhythm of 2PM songs.
In fact, all I wanted was to listen to Taec's heartbeat! Perhaps even catch a glimpse of him tearing his shirt off as he used to...(that would have been worth at least a full point in the final score)

Indeed, my whole reason for watching this drama was really just to support our beastly idol and I had no expectation whatsoever. On the contrary, more than expectations, I had a bunch of reservations about the vampire theme, one that I explored to exhaustion in my teens and that holds little to no interest for me nowadays. Thus, I ended up putting this drama off for months while waiting to be in the most forgiving and neutral disposition possible and, when I was finally able to start it and watched the first couple of episodes, I found myself positively excited!

The series begins with an upbeat and comedic tone à la "What We Do in the Shadows" that makes for a refreshing opening. I genuinely liked the vampire trio dynamic: they are endearing loosers that struggle to keep up with the times (which I find infinitely relatable now that I am in my thirties...sigh!). Also, their beef with modern capitalism is hilarious and a great variation on the abused immortal-handsome-and-rich formula.
Personally, I think Taecyeon is formidable when interpreting whimsical characters. He has great comedic timing and a natural talent for slapstick with his impressive range of cute/ridiculous facial expressions and overgrown limbs. I enjoy his acting the most when he unleashes his potential for antics (i.e. his crazy villain in Vincenzo is absolutely brilliant). I think he fares particularly well in balancing being extra without being actually over the top. That is what convinced me that the drama had robust enough premises to evolve into something worthwhile.

But mine was, definitely, premature optimism since the series takes a 180° degree turn around episode 6 or so. The tone gets abruptly serious. The story literally flatlines (ahem...) as we suddenly loose all the potentially original plot points in favor of the dullest of fanfictions. Because that is what I was reminded of while watching this drama. Especially during the party episode which employs one of the most popular romance tropes in its cringiest declination and with the most uninspired jealousy scene ever (honestly, I'm usually a sucker for party scenes done well, Pride and Prejudice style).
At that point I kept watching just to finally discover who took the gold.
The storyline has zero depth: everything happens without explanation, with an impressive number of plots non-sequitur, and because Cat-ex-machina said so.
The romance left me completely indifferent and the modicum of sympathy I felt for Woo Hyeol was totally built upon my pre-existing bias regarding Taecyeon. Not even the happy community scene at the end was enough to reanimate my k-dramatic heart.
The open casket funeral was too much...

In conclusion, I wouldn't recommend watching Heartbeat, not even to Hottest, although I made an intriguing discovery that partially redeemed this viewing: Park Kang Hyun. He can act, he can sing and he is cute as hell. Hope to see him in a better drama next.

Female Empowerment Score 2/5: Joo In Hae is written as inconsistently as the rest of the characters. In the beginning she is this tough, combative girl. Her personality traits are clearly the result of trauma (the customary kdrama unlucky orphan backstory) and make her fiercely independent and extremely reserved. She keeps her distance from others but is also ready to fight in order to protect the weakest and heal the wounded as a trained nurse (I liked the school nurse plot). She was preoccupied with mere survival for so long that she forgot how to enjoy life and be carefree with her heart. In the beginning, she is relatable and convincing (I love how Do Shik gets her and tries to help her without her noticing). But then, suddenly, we are told her character experiences growth (e.g. she falls in love, accepts help, makes friends, forgives her father), without actually being shown how or why. And, furthermore, she becomes insufferable (the acting follows the script in its decline). Despite being somewhat empowered by her character arc, she doesn't seem to have gained any real agency.
The writers didn't really care for the other female characters either.