Does anyone know how to get the revealing black suit? I've played this game before and, as I understood it, I had to talk to the guy in the alley until he tells me to get a new outfit, after that the shopping event with Serena's friend should be unlocked, but it doesn't start that event.
These are different outfits, the Black Suit and the Revealing Suit.
For the Black Suit,
buy all the lingerie (and maybe the Fancy Suit? I forget, honestly) and Serena should comment on seeing Angie about other places to shop. The Revealing Suit is
the reward for the Lover's Park questline. Keep going to the park after work and talk to the man, doing as instructed until he says Serena should spice up her wardrobe. Shouldn't be long before Angie has a present for Serena.
If you get stuck, make sure Serena has her passives, i.e. Reduce Shame I-III. You should also do
the Science Club questline to get Panties Off/Commando passive. Although you can buy it, there is a warning that doing so may interfere with normal game flow.
I'm stuck on the last part of the boss, he hits me twice and then I revive. There is a way to beat it??
Level up and buy skills if you haven't, then spam the sweep kick or whatever you have that disables the old geezer. Keep him down and push in damage, even chip damage. It's not a stand-up fight because he's a demigod of sorts and Serena is so full of repressed horniness and spunk that she's effectively a supercritical immortal succubus. It'll resolve eventually.
The thread has further specifics, quite a few have struggled with the final boss.