tl;dr: A manga with an interesting foundation but one that isn't built on well enough.
This manga has a pretty solid core plot. The protagonist, Haruomi, is solid both in terms of having a pretty amusing and likable personality and in terms of having an ability that results in him having a good spot in the story where it's enjoyable to see him getting involved and having an impact on things. The main heroines, Zilch and Murohime, are also solid and the relationship set up between them and Haruomi is interesting to watch get fleshed out, though the twists surrounding them were pretty predictable from the get go. And while the plot does involve a lot of other elements, these relationships were pretty strongly focused on throughout so that is enough to hold up the plot decently.
That was unfortunately necessary because the elements outside that weren't all that great. The biggest issue with most everything else is that it didn't develop things enough. The world itself felt underdeveloped in that it doesn't really world build all that well, wherein a lot of things such as the ultimate goals or motivations of Goetia or how the demons or heaven fit into everything are left nebulous. The manga also ends with a lot of the more subtle plot threads involving such subject matter left unresolved, which makes it feel like things haven't really been properly resolved overall.
The way supernatural elements work is also left pretty unclear. This includes the broader more overarching elements like how what are known as Branches work. But more importantly the abilities of the main characters are also really underdeveloped. Haruomi seems to have a really strong and interesting power set, but how it works feels pretty random. And the powers outside of that mostly feel kind of dull and also kind of random, especially towards the end. This results in the combat situations not being as exciting or interesting as they could be.
The plot in general also felt sort of rushed with not enough build up to or time spent on major events, which prevented them from being all that impactful. I feel this is especially true for the ending which was built up to to a certain extent, but not to the degree that a finale deserves and though the ending wasn't terrible, it felt kind of weak and thus not that satisfying. The comedy was decent and helped with the tone and pacing, but wasn't really enough to hold up the manga overall. The art is excellent and used really well with good framing and good character designs.