so after playing in english mode (selectable at the main menu, doesnt have anything besides UI partially translated atm) to get the kiss skill need to get the necklace of the other angel girl (who goes succubus) by getting it from the chest in the room where airi gets her gear back. its the chest in the deadend right side as your ascending the platform section. Go give it back to the angel girl who kisses airi, afterwards, talk to her again and choose second option to get the skill.
Theres also apparently 3 gear types, gem, card, and...accessory? after beating succubus lady, the chest she drops contains her angel card that you can equip, not sure what effects it has. After you land on earth and rescue the fairys, you get the prostitute card from the "Thank you for Playing" corpse.
Also color me suprised theres a lvl grid system. apparently when you beat an enemy and it drops those energy orbs, you can use them to lvl up airi (second option in menu)
Sorry in advance if this is all redundant information, didnt feel like reading through 30 pages to see if anyone found this stuff