I'll probably end up writing how I feel about both games here since BS2 isn't on this website yet.

BS1: I think this game is incredibly neat especially as an enjoyer of Dark Souls 1
I really liked how open ended the game is from the get go, you can kinda get your ass kicked immediately if you go through certain paths but it's fun to see how far you can get before you end up Dying and lose all your Souls™
The art style while initially jarring ended up becoming pretty endearing to me, the gritty and sketchy look to all of the characters really fit the atmosphere and narrative.
The combat is funny if not a bit (very) unbalanced. You get the option of a few classes at the start and while melee does work quite well for the most part magic is stupidly busted which I thought was a pretty accurate mirror to Dark Souls 1. It's definitely not hard to break the game just in general though with your stats going crazy high due to soul leveling and all the permanent stat boosts you get throughout the game, which is a bit unfortunate when you get to big dramatic fights and you just end up oneshotting a boss.
I think one of my favorite things about this game was the atmosphere it had. Some of the areas and battles just made me feel super uneasy, the use of music and the element of surprise that it had gave me a similar feeling to some of the really creepy battles that happen in LISA.
I really enjoyed the overall story of the game despite its shoddy english translation, some of the endings in this game are a real punch in the gut and the party members you get are all pretty cute which makes the Despair in certain story beats feel all the worse
Black Souls 1 has a lot of interesting ideas and does some really silly stuff which I definitely enjoyed a lot. I'm incredibly excited to play through Black Souls 2 after playing this
oh and the music goes hard

BS2: I love this game