There were some funny moments, but I found the overall concept too bizarre and random and chockfull of plot holes tbh. I wouldn't continue the series.
Karma was WAY over the top, who turns into a complete psychopath after finding out society cares more about good grades than what is right/moral? I liked Nagisa, he seemed nice and sweet. Otherwise, I dont think I got to know any character enough to have any opinion on them
I've read manga before, and this was typical shounen art style imo. I'm unsure if I'd classify it more as shounen or seinen, espessially with the very final image.. that.. uh.. looked a little risky. I'd say it would be high-age-end of shounen.
As for pacing and depiction of time, that was easily slotted into the fact he kept teaching different subjects and the fact that the students kept going "I'll try again tomorrow"
I wouldn't know what I'd say to the artist. Maybe: Why did you choose to make his face the way you did? It's very unique and very much like an emoji.
Anything else? Hmm, the students were too relaxed. Too much "we have all the time in the world" attitude when in fact the whole premise is they only have a year to do it. Like, that one guy who decides he's going to work on his future as a pitcher? WHAT future my man???