The provided walkthrough didn't seem to follow the game all that closely, at least on the path I was trying (romance). We definitely could use a better walkthrough. As for the other two gals (besides your sister), yeah the walkthrough was very vague for them.
My other complaint would be that, at the end of the game, sex was discussed but not shown on the romance path. A render or two would have been nice...
The camera flash function was removed between the demo and this version. Yeah, it was just an extra (probably unnecessary) step, but having to remember to turn off the flash on your smartphone camera was a nice touch... Chalk this one up to an extremely minor nitpick. The heart beating level at the upper right is a very nice way to keep track of when you need to hide during the shower scene.
This game pretty much forces you through a bunch of replays of the various paths to see all of the content. I'd love to see a full CG rip of the art, so that I don't get bored replaying this a bunch of times...
Nitpicks aside, it was worth the download. Sis is quite cute! As is that new gal...