Playing version 1.0.3.7 .. Not gotten through it yet, but have played through the first one, and gotten quite a bit into the second.. Thought I'd chime in with a little review..
Firstly, the graphical quality in this game is excellent. All the girls are sexy and looking amazing. Render quality is awesome, and there are decent animations in the game too. (Well, compared to the average XXX game, I'd say the animations are excellent, but still way of playing like a real video
It's a sandbox, but there is a good hint system so I haven't got stuck yet, so viewing all the sexy content is pretty straight forwards..
There's also decent sound, and some voice acting, which adds to the game if I'm playing in a context where I can actually avoid turning off sounds
The game has an option system for what action you want to do, or what you want to say. If you choose the "wrong" option, you typically get some more or less failure scene playing, and you'll have to test the right option a later day when retrying to get further. Thus, picking the wrong option leads you to see some extra content you'd otherwise miss, so don't fuzz about having to pick the right ones all the time.. I don't know of any option that will affect game play permanently, so the it feels like a fairly linear path, where you can pick wrong and have to restart.. Often you only have wrong options, because you need to pick one of them first to learn what you should do and enable more or other options later.
To not get too repetitive, the game often skips content that is the same as a previous cycle, so you don't have to replay a lot.
The game has an obvious setup as to relations between the characters, but as you input the relations yourself to begin with it side-passes censorship. Sadly, that also means voice acting can't say the relations, nor the configurable player name.
The story is written in good English. I'd say the story is fairly decent from the parts that I've read, but there's so much of it. I quickly get the temperature up looking at the amazing girls, so I'm having a hard time not skipping through a lot of it.
I'm using the hint system a lot, as I don't want to go through all location and times of day to see where and when I need to be to advance the story, which leads to less engagement. The game could possibly have a non free-roam version where you automatically moved forward. The alternative to make it interesting enough to not use the hint system is pretty hard to manage. That would quickly lead to a game with far from linear progress, where the devs would have to put a lot of effort into content few people would see.
All in all, even though I'm not a big fan of the time travel part, the game is of very good quality and highly recommended