Definitely a worthwhile series, albeit with flaws. Below, I outline three sharp criticisms where I think the writing stumbled. None of these missteps is fatal to the story or characters. Definitely a case of falling short of potential greatness rather than a series that misfires on every level. Throughout, the acting, directing, and writing (script/diaog) are mostly high quality. These flaws owe to writing (story structure, story choices) that I believe undercut this series' chance to rank among the all-time greats.

Three criticisms:

1. The high school era was more interesting than the adult era.
-- First: Two boys wounded by family, stuck in unpleasant circumstances. Finding their way toward solace by finding their way toward one another. That is a damn good premise for a BL romance. And our young protagonists had a good thing cooking, too. Enough character, story, and emotion introduced in eps 1-2 to sustain a whole series. Instead, the writers chose a time jump prior to working through all that potential. Second: Two adults wounded by their past. Placing obstacles in the way of their own solace. That is a less satisfying premise for any romance, BL or otherwise. And our older protagonists induced this viewer to contemplate in multiple episodes whether these two humans belonged together at all.
--overall, the bipartite storytelling does work. And yet. Because the later episodes prove far less compelling than the earlier episodes, the result is a series where both timelines underperform the potential baked into the characters and story. Again, to reiterate: not fatal flaws! Still a compelling series.

2. That was the most preposterous time jump any BL series has ever foisted off on viewers.
--12 years? Really? To Be clear, the idea that high school sweethearts reconnect in their early 30s is not a problem in itself. Indeed, one could easily build a whole series around that premise as well. But during the intervening decade, the two individuals ought to have lived some life, grown into new people. Even if the reunion rekindled dormant feelings, the vibe should feel like two near-strangers starting fresh--because none of us at 30 is the same person we were at 18. Characters ought to adjust to Who Are We Now? Here, it is as if both characters have been in stasis since high school. Pining away for one another yet not reconnecting. Apparently (and we must surmise, for the writing reveals very little about how the two protagonists spent their decade apart), neither of them moved past the other. No intervening romances to provide the sort of life experience 18 year Olds didnt have. They do not reunite as older, wiser versions of their younger selves but as emotional cripples stunted in growth at 18. No more savvy about love at 30 than as callow teens. I am all for reigniting the lost flames of a youthful passion. But not for wasting the entirety of one's 20's waiting for something that did not work out. And after 12 years apart, trying to pick up where you left off? No no no. So to be clear: my gripe here isn't the exorbitant length of this time jump. It is for the illogical way in which the writing fills in the gaps.

Note 1: The series hired two actors roughly 25 years old to play the same characters at age 18 and age 30. While that tactic of "splitting the difference" does work visually in the sense these actors can believably play either age, it is nonetheless jarring to see "Twelve Years Later" pop up on screen and have the actors look as if no time has passed. (The make up folks dyed Dad's hair gray. Effort!) As much as I admire the performances of these actors, I think a time jump of this magnitude warranted recasting the parts because that would have emphasized the natural growth humans experience in transitioning from impulsive but callow youths to responsible adults. Here, the actors' non-aging just added to my sense that these two characters got stuck in high school.

Note 2: The obvious BL story that comes to mind with a comparable time jump is His The Series and His The Movie (Japan). That production team did re-cast the TV actors for the movie sequel. The film plot also depicts the rekindling of a dormant romance, one also spoiled by one party abandoning the other. But those characters had to work to rebuild trust, with no expectation of resuming where they left off. In that telling, their present-day situations mattered more than the shadows of the past. His (film) is one if the best "gay men overcome obstacles to create family" stories I have seen from any continent or any decade. Playing the time jump effectively is one reason why. The missing and unseen years had an impact on the characters that added depth to that story.

3. The fraud subplot was unnecessary.
--Sometimes writers fall victim to a temptation to layer additional challenges into their story. ("What new horrors can I inflict on these characters to ratchet upthe stakes?") Often, simpler is better; editing, warranted. Here, the fraud adds nothing to the character. His story was already compelling. Indeed, it may have become more poignant if every detail stayed except the fraud. Dreams shriveled (like a raisin in the sun) are a basis for tragedy. Explore that concept without destroying the character's moral character. If his personal demons had driven him to suffer in silence rather than to overt criminality, a compelling emotional journey is still at hand. Criminal fraud, in fact, makes any character less sympathetic even if his motives are well-explained, which these were not. Adequately explained and justified--yes. But "adequate" falls short of "well-", just as I rate Let Free falls short of elite status. The character had many burdens already, and this self-inficted gaffe demeans everything he hoped to do.

In summation, Let Free is a very good series. Certainly, worth one's time to watch. And the ending eventually proves sweet and affirming. Flaws in story structure undercut the bid for greatness, as does the too common penchant to withhold information from the reviewers via editing. Here, flashbacks in the penultimate and finale to the high school timeline fill in missing information help us to understand why each character behaves as he does after the time jump. But honestly, the middle episodes would have been far less frustrating if those details had been in the open earlier. Handled properly, the romantic story would play as a tragedy rather than the stunted, slow-burn mystery tale we got.