Gonna be honest lads, I finished Luna route (plus after story) and then proceeded to slap a score on and then never looked back. You might have come for the trap or the goth loli or something, but you will most definitely be leaving addicted to Luna-sama. She did win Getchu's best character category three years in a row for a reason.
Apart from Luna, the rest of the heroines are fine if not outstanding. You have the tomboy, the OHOHO and the androphobe, but they're pretty standard. Apart from that, the walking Kaiba clone comes with his own BGM so he's pretty memorable. Also Asahi is a good trap. No homo.
Really though, just playing Luna route is enough. You can try the other ones but trust me when I say only one route feels canon and right.
Praise be to Luna-sama.