SabiHakuhei

Difficulty doesn't change in the main game.  I believe the usable character numbers are between 17-18.  I do believe they allow you to increase game difficulty in NG+, but I'm not sure, because I might be getting it mixed up with other games from the genre.  Understand, it's been two years, so I don't remember a lot of the details.  The game does get harder later on, primarily because of the limited usefulness of characters gotten late (growth issues due to the way the game is structured) and the sudden spike in difficulty at the end. 

Using random nihongo kotoba that people wakaranai is sugoi.

Code Geass
Nichijou
Drifters
Ano Hana

same here. we pretty much learned the same amount of japanese too (hiragana, katakana, 550+ kanji and some vocab).  i tried to read (had a quick look) at Love Revenge and gave up after an hour or so. even if you understand every word and/or use a dictionary, every sentence feels like a small puzzle you have to stitch together in the right order.