I think everyone else said things the best way possible, so I'll just echo what they said to reinforce points that stood out to me:
- Good art
- Characters' personalities are clear
- Needs music & sounds
- The magical girl (boy?) segment and battle system seems kinda shoehorned in there; needs to be either fleshed out or remade to fit the story better
- It took me a while to understand the ending, and even then it's not clear to me why Haruki is doing what he's doing