I'm going to preface this by saying first that I really like this story for several reasons.
To me it's a refreshing story when you look at other currently popular manwhas. It's not a tower manwha, no gates are opening on earth, and it's not isekai! Despite the protagonist having a knife it's not a solo leveling copy in any way (I've seen people react this way when seeing the protagonist sadly...) and I'd compare it more to Men in Black than any manwha I've read so far.
I'll admit the summary of the story sounds a bit ehh, sure it's relateable but it doesn't tell you what kind of story it is!
The protagonist has been a prisoner working to pay off his crimes for 800 years to a dimensional space comitee, that basically has all the power. He's a prisoner because he's done a terrible crime that made the comitee erase his memories and change his identity, which can only be regained by paying off his sentence through labour. This means that he's been to several dimensions working different jobs to earn talents, an all powerful space currency. The story deals with him after he's been designated to earth, a far off planet on the periphery, so he's literally the foreigner on the periphery. On earth he does detective work to earn more talents and as the plot thickens the stakes get higher and the story more layered!
The protagonist starts of the story already competent, this dude has seen some shit in the last 800 years and it's clear to the reader. He's not a newbie who got an OP skill or anything like that, he's a strong black mage and certainly has some OP abilities but it feels warranted. The story also isn't about bruteforcing his problems, he functions as a detective and uses his experience and connections on earth to help him solve different cases. There are certainly high stakes battles, but there's also a lot of investigative detective work, and some comic relief scenes sprinkled in here and there.
The characters get development over time, several characters have their own motives, hopes and dreams. It doesn't feel like they're there for the protagonist to look good. No, a lot of the characters in this story are actually competent on their own and also have their scenes and moments to shine.
World building, a sci-fi fantasy like this story has plenty of room for good world building. I think this one does it well, the world building so far fits the main themes of the story well, races and different worlds are fleshed out, there's politics, tax offices, different bureaus, individual history for different races, different religions, and so on. The story is good with details and a lot of elements are very intentional (even if it doesn't seem that way at first
).
Interesting themes: Can someone who did a horrible crime be reformed? Is it better to simply die than to be a prisoner working off their sentence doing labour? Racism, politics, and theology are other themes that come up. It's the kind of story where I rarely feel like there's good people to cheer for and bad people to boo at, the situations are complex with an entanglement of politics, race, identity, and morals.
Personally I don't find the manwha difficult to read, but it's the kind of story where one needs to be patient and read behind the lines. Currently there's only 48 chapters of the remake, but there are 323 completed novel chapters + 50 ongoing extra chapters! Where the manwha currently is there's still a lot to be discovered and I can't wait to see how the novel chapters will be done!
In regards to the remakes art compared to the old art. I only found this story after the remake was a thing and imo I would've never read the story based on the original art. I like the current art a lot, sure it's not SL god tier but it's good for what it is and the protagonist has this fantastic dead eyed seen some shit look lol. To me the remake art also resembles the novel cover art better, but korean novel covers are also an entirely different beast!