Taxi Driver is a stellar series--highly recommend. I greatly enjoyed watching.
Part 1 has no spoilers, Part 2 has some story line reveals/spoilers but not much. Watch series first. I call out a glaring blunder and then give some ideas for Season 2 ( dream on right?)

First--kudos to the concept developer/writer for engaging us on a difficult social topic: when and how is justice served? Does revenge come with a cost and is the cost worth it? Does the justice system (the prosecutors/prisons) contribute to rehabilitation or keep victims of crime safe? Who helps them when a murderer is released from prison who can then kill again? Does forgiveness factor into healing trauma from violent crime? Show's motto: can evil be overcome by doing good? The crime stories are adapted from real life in Korea too.

CREATIVE and original drama--The vigilante justice taxi team's CEO Jang Sung Chul portrays the ambiguity, the human foibles, the mistakes made along the way and this is what makes the show so compelling. What is closest prosecutors and the revenge taxi can come to achieving justice? Even the clients hesitate when deciding to push the 'yes I want help with revenge' button--these aspects add so much to the dilemma and story telling. The Blue Bird help group he directs gives us the backstories to keep us emotionally invested in a BIG WAY. Then, such satisfaction when the clients get reparations/justice such as $ for college that was scammed, and the team members take turns being the giver--which adds to their own healing/sense of making justice out of things. Just wonderful. Could be 5 seasons with this material.

Lee Je-hoon is an outstanding actor and while his action scenes are great and deserve the high praise... do we really need an Ironman action figure who can floor a group of hammer wielding men all by himself? These fights were a few too many and detracted from the story as they became just silly like all of sudden 'lets make an action hero show.' Je-hoon's undercover characters were fantastic, and added needed brevity and comedy. Perfect for this role.

Part 2 SPOILER ALERT Please watch series first.

Major writing blunder when Kim do ki sets a bomb for the porn CEO, drives off then sees prosecutor driving to the scene and does not have someone tip her off by burner phone 'don't go near shed-server there is a bomb.' She could have been killed ( she was injured). Just some lazy writing. I understand the lead writer left mid series ( big mistake they should have listened to the writer).

If there is a season 2, there are rich relationship potentials especially for Do Ki and Ha Na- not romance--but much needed human connection for characters--some deeper communication say how to heal and move on from trauma. When Do Ki has 2 major melt downs due to unresolved trauma and Ha Na is there both times and no hug or comfort? Just staring like a deer in headlights? Waste of this hugely talented actress. This was a moment for us to feel something more towards Do Ki, he could have reached for her hugging -sobbing- releasing and this would give the prosecutor more compelling reason to empathize with him personally and with the Taxi team's methods and reasons too. She joins later anyway--make it a believable build up. A missed opportunity.
And just some basic human kindness. They all seem to lack warmth of human touch. And for Pyo Je Jin too. What a talent! Did not like/agree scene when she is full blown traumatized and Do Ki wanted to go to her room, CEO said no--let her 'process'. Seriously? Even though he may not been able to help, why not allow him to say 'I'm here if you need me.' I know they are all damaged by trauma but still let them be more than robots! Do they need a woman writer on this team or is it all 'more action figure fighting scenes' instead of time on characters and how they evolve their approach to justice making and bond as humans and be tender towards each other too.

Idea for new calling card as they re-invent the taxi revenge approach Season 2:
BEYOND REVENGE IS RETALIATION THROUGH JUSTICE.
WE WILL DO IT FOR YOU.
DON'T DIE. CALL.....