The theme of self - improvement is also there. For example, Kazuma, the main character, starts as a bit of a loser but gradually grows in the new world. And the light novel also has a theme of satire, poking fun at common tropes in RPGs and fantasy stories.
Darkness is definitely one of the most interesting. Her masochistic tendencies combined with her role as a knight make for a really unique character. Kazuma is also interesting as he's a rather unconventional hero, more interested in a comfortable life than grand heroics.
I'm not entirely sure, but it's very likely. TvTropes is a comprehensive database for all kinds of fictional works. Given Konosuba's popularity, especially in the anime and light novel world, it would make sense for there to be a section about its visual novel on TvTropes. You could check by searching for 'Konosuba visual novel' on the TvTropes website.