There's a 1.1 patch out. Fixes stuff like CG not appearing gallery (i think the sauna events), addition of a Heart HUD element (to track affection), and making it easier to invite Oki/Okan to the party.
They nerfed getting money from the minigame but I only ever played it once. You can cheat the money and gifts by save editing, which is the entire point of the minigame anyways. Skipping the work minigame won't prevent you from accessing the Spa. But then again, you can also cheat their affection level so you don't have to give them gifts.
Apparently, there are secret CGs where you get to threesome with two of the four main guys, and a True End Flag for the one guy. As far as I know, sex scenes from that guy only happens in the bad end.
The random NPCs also have one secret sex scene I'm guessing from looking at the img files inside the game. But I don't know how to make them happen in-game.