Kakegurui Midari is a sequel to Kakegurui with Midari from the main series as protagonist or maybe even deutaragonist (she seems written as a pushing force for the protagonist). If you liked Kakegurui you will probably like this one. Midari already was a fun character and now we get to see more of her. I'd recommend to reading it after she appeared in the main story. Have only watched the anime btw.
Story 6/10:
The Story of Kakegurui was never meant to be something outstanding and so don't expect it to be different here. It serves its purpose and gives you some insights of the already known character of Midari, which made her more human? Our protagonist is a really intresting and conflicted charcters to say it at least. The story probably will stay at a six, due to the concet and the way it was played out, which isn't bad I still enjoy reading it.
Art 9/10:
The Art just works. The expresion were made perfectly cruelsome. Really detailed artwork with panelstructures that lets you read it like being in a float state.
Character 4,5/10:
The Characters are only there for being there. They don't save any other purpose and are pretty forgetable, except Midari and Ayame. While these too are fun to watch the other appearing characters have no really a character or are pretty much the same. While I myself like this aspect, cause otherwise it wouldn't be Kakegurui, I can't rate it any higher. I've read series with much better characters to do that.
Enjoyment 7/10:
The Enjoyment is always there. Can't await the big plot twist at the end of every game. Somtimes it is forseeable, sometimes I found myself asking "How do you pla to come out of that one". It gives you what you asked for - more Kakegurui, more gambeles - and does a good job in doing so.
Overall 6,5-7/10