Forwarning that I am posting this after unlocking all characters / weapons and am still playing, but did beat the first level of darkness so felt it was fair to give my review since the game is not much different on (from what i've been told). Now with that out of the way...
It's charming, I like it a lot. I've never been a huge fan of action-roguelikes or bullethells, but I do like what flanne has done here. The characters and weapons all seem solid in their own way, none feel significantly weaker, but some feel suspiciously strong. I think the design is nice and clean, very fun gameplay mechanics and overall just a great game to sit down and bang a run or two out in when I have an awkward amount of time... especially with "quick-play" being a feature I find very accessible. Solid fun, will keep on grinding through the end of the year.