There's a lot to say about Wada Makoto, but I'm not sure an anime site is the right place to find it. His life as an illustrator, essayist, and film director didn't begin in earnest until his short animation stint ended. In his late teens he sent a fan letter to James Stewart after watching The Glenn Miller Story, complete with a drawing of Stewart, and the response and praise he got to the letter from Stewart was the start of his life as an illustrator. His freelance years, where his work on everything from book bindings for Murakami Haruki to his extensive list of entries in the Minna no Uta series would win him more widespread recognition, would begin about fourteen years after sketching Stewart, and his contribution to the anime world fits right in that window.
The source of this foray into animation probably had less to do with the medium and more as a way to experiment with ideas, mostly in illustration rather than in storytelling. His first piece exemplifies this; he participated in a 1960 NHK storytelling program by providing eight minutes of rough illustration to accompany a narrator reciting Miyazawa Kenji's Oppel and the Elephant, the second of the three stories packaged as 3-tsu no Hanashi. Of course Wada had no say in the story, but Miyazawa's stories are stories that can be illustrated wonderfully, and while rough even within the omnibus there's a charm to his drawings, clearly not meant to be important as animation more than as art.
With that said, it doesn't look like Wada could've come up with that rough line-art style in a vacuum, especially considering how different it is from his illustration work. Not that he had to. Wada kept company with the newly formed Sannin no Kai, a group of experimental “rebels” in animation riding the avant-garde wave of the late 1950s. Wada's writings aside, it's pretty clear what effect the group had on his few animations, particularly the most well-known of the three (in the animation world at least) Kuri Youji. Wada would direct Murder and take the 1964 Oofuji Award for it right as the Sannin no Kai winded down, and barring his Minna no Uta productions it would be his last independent animation work for twenty years.
To me Murder is emblematic of the early years of the Oofuji award, minimalistic in its motion and color palate, repetitive in its structure, and yet strangely intriguing and new. I would say that the comedy, however dark, is much more enjoyable than Kuri's, even though Kuri appears much more frequently on the experimental award circuit of the 1960s. In it Wada gives a dozen different genre takes on a locked room murder, all equally absurd and equally anticlimactic, condensing the three-act structure of any murder mystery conceivable into fifteen seconds or so apiece. Whether it ends with an arrest, a romance, or anything else, I just feel bad for the poor murder victim whose death barely matters past the maid finding them dead on the floor, and that feeling is highlighted by just how fast the next murder is set up. For ten minutes total, the whole work is tight and smart.
I'll avoid going into the Minna no Uta years and his help in creating Okamoto Tadanari's Hana to Mogura, itself an Oofuji award winning piece, since those are better covered in different articles. But a comment is due about his one other animation work, popping all the way in the late 1980's. By the time he produced and directed Kaitou Jigoma Ongaku-hen, Wada was an award-winning film director of at least four years, and I couldn't guess at why he did an animated musical calling back to the old French thief Zigomar. Not that Zigomar was a foreign topic to anime; a series of animations inspired by the film were one of the central causes of regulation in the early 1920's Japanese animation scene. Whether Wada wanted to hearken back to that time with the setting and musical is beyond me, but regardless his work is a slightly more detailed and colored version of his older style, albeit similar in how it's constructed of disjointed shots and vignettes.
In that sense it caught the musical spirit pretty well, but there's not much to say about Kaitou Jigoma besides that style, other than the fact that twenty years of music videos taught Wada how to be cute and succinct with his musical numbers. Then again, that's also to be expected of an illustrator of Wada's caliber, a cross-pollination we don't see quite as much of nowadays. With a reasonable sector of modern independent animation tending towards that storybook style, it'd be nice to see more works from old hands like Wada and Tamura Shigeru lending their extensive work outside animation. Also I wonder if Wada has the rebellious spark of Murder still in him today.