Master Keaton is indubitably an anime series that will make you smile in its aftermath, as it provides a charismatic protagonist juggling life as a archeology teacher with his numerous travels around the world, helping other individuals in the process.
Naoki Urusawa, the creator of such series as Monster and 20th Century Boys, created a gem of a series with Master Keaton that does well in its respective aims. Honestly, I haven't watched a series that made me feel this good since watching Kino no Tabi. Keaton, as a character, is a bit of a humble, good-natured genius, often utilizing his former combat experiences while working for SAS to aid in helping other people he encounters. Everything from saving a little girl from her crude grandmother's bodyguard to warding off KGB thugs. And at the end of the day, he seems to solve the most complicated tasks with the most simple of approaches. Another McGuyver? In approach for some terms, maybe, but Keaton's more likely to have a sweatdrop or two run down his forehead in embarassment at some of the things he encounters, and he's not quite as bold in his approach - as he noted in one of the episodes: he'd rather avoid conflict if he could help it.
It's incredibly hard not to like, or even love, Keaton, especially when in a seemingly episodic progression, you come to know so much about his character with every adventure he undertakes. The series even allows you to share some of his fascination with different societies and the stories he comes to know in his travels. Even if you don't like archeology/history/learning about ancient societies, this series does a nice job of immersing you into that scope without taxing your brain in the process. Yet, I provide a word of warning: you really have to love progessively paced series to be able to enjoy and see the fruits of the execution here.
What I would note as constructive criticisms of the series however, is that there is not just one plot to be had in this series, there are several, and that may be a deterrent for those who look for just one running story throughout. However, I would argue that measure is fully intentional, and I'd also say that there are bits and pieces of a tangible one if you approach it on the note that the series is centering around Keaton's pursuits. One episode you're learning about how he keeps cancelling classes on account of his travels, and another you learn he's a divorced gentleman who seems lonely but still carries a good attitude on his shoulders. Keaton is the cornerstone of this series and his interactions with the characters and each case are what drives it home on most measures. There are some stories that are a little slower than others and may not be as quick to impress the viewer (I liked the episode about the archeologist protecting her local ruins, but I'll admit that episode was a bit more story heavy than it was action based, so there's a give and take to consider as you go through it), but they're still above the average story you may find in many contemporary series, and with enough flesh to pinch from in the aftermath of it all.
There is regular consistency in the quality of most stories here, and each features a precise telling of how Keaton comes to be a part of each. That doesn't mean that it's steeped in just a slice of life mentality - there are plenty of nice action/suspense/comedic moments to be had in this series, just presented in a manner that's easy to digest and doesn't speed through like a bullet train.
It's beautifully written with nice execution, and it's rare that you see an anime series do all of these factors in such a way that's both soothing and mature in its construction.
The animation takes a classic feel for the most part through the series, from the construction of the settings it replicates and the actual depiction of famous figures (Czar Nicholas II, among others) to the character designs. It follows the manga designs quite closely, and if you liked the style of Monster's character design, then I think it would be something to enjoy with respect to this series as well. However, the coloring isn't nearly as rich or dark as Monster, and it's possible that it might have been noted as a factor of its year (1998). Then again, that may be reflected in the tonality of the series, and if taking it in that consideration, it's a well-noted fit.
I approach Master Keaton with some sembalance on its overall sound. The soundtrack stands out on its orchestrated pieces more than its vocal performances (I think people will like the ending theme, but I don't know if it particularly jumps out when considering it on a stand-alone factor). The opening theme is probably one of my favorite instrumental compositions in its calm blend of traditional instruments and Scottish derivations (bagpipes included). It suits the atmosphere quite well, as does the instrumental pieces interspersed throughout the series itself.
I loved the original Japanese vocal cast. Keaton's VA, Noihiro Inoue, is well matched and provides enough humor, spontaneity and wit to drive Keaton's character with the composition of the series. The English VA cast surprised me too; I honestly didn't think it would translate as well as it did in the aftermath, but they matched each of the characters, even the secondary cast, quite nicely.
Master Keaton is a character driven series as much as it is noted within its story structure. As much as I've already noted about Keaton's character, I'd like to note that the secondary cast of characters are a nice fit conducive with the aim/structure of the series. Some are memorable/charming in the moment, others don't have as much considerable pull, but they're still genuinely fun to watch. The only point of criticism I would make is that the villains aren't so much detailed as they fit with a given scenario. Again, I believe this to be intentional as it is an episodic series, but those who may prefer a primary antagonist with a bit more dimension may find themselves at a bit of a loss with this series.
Some antagonists are clearly stronger than others, such as the former Scotland Yard agent who seems to resist Keaton at first when Keaton tries to intervene with an operation, but finds himself admitting that Keaton proved more of a "Pro" than himself.
Overall, definitely a recommended watch. If you like stories that take on a traveling spectrum with interspersed stories, a blend of action, subtle comedy and adventure, and a likable protagonist who has the ability to make you smile after each of his pursuits, then Master Keaton is definitely a series you should watch.