"Will you be able to cross that line with #2?"
Spoiler alert: You don't. The closest you get to that is rubbing her coochie. You don't even get to whip your dick out.
The game sells itself to be more than it actually is. Essentially, the game is played like this: You chat her up to raise her affection and advance time. If you upset her or try to grope her, you lose 2 affection and advances the time by about 1/5th of the total limit. At the end of every 2 "stages," you get a minigame. There is a maximum of 6 stages. That's literally the whole game. It's technically playable and I haven't experienced any bugs, but it's simply not very fun.
The story and dialogue is a bit dumb. Our heroine, #2, is described as a loli, despite being a legal adult, looks nothing like one, and talks more like a tomboyish highschooler than anything else. She comes off as reluctant rather than naive and her main interest is in fish and nori snacks. You rarely get any personal choices in what you wanna ask her and what little choices you get simply affect her affection level. As far as I can tell, the story is 100% linear and whether you grope her between topping off her affection or simply stick to just chatting with her makes no difference whatsoever.
The minigames themselves are simple, but explained in a very confusing way. The first one is a shell game. The second one involves you collecting coins while avoiding sea mines (which you'll need a LOT of, if you want #2 to be naked, to play the shitty bonus mini game, and still have enough to buy recovery items), except the entirely of your hitbox is the tiny bobble on your shoulder, followed by a short (~30 minute) RPG section with lame dialogue and absurdist humor. Why the panty thief in this section is Kindaichi from his Case Files, I have no clue. The last minigame involves removing sushi from our heroine's naked body by aiming for a certain number on a fluctuating gauge. After that, the game more or less ends.
tl;dr: There's pretty much no story, the minigames are reminiscent of early 2000s Newgrounds, and the only reward you get for putting up with all this are pixel art still images. There's only like 8 in total. If you want to relive the tedious glory days of Newgrounds, but with less penetration, this game's for you.
P.S. There is no freeplay mode. If you didn't make multiple save slots, you will need to replay the game to grope her.