I've been told this is a very realistic sandbox game, so I tried to apply the MC's methods in the real world. Turns out the game is not realistic at all. I'm now writing this review from prison. Bah.
Excellent game. Funny, lighthearted porn-plot. Good animation, nice looking models, and no grind. Pretty much all scenes are hot. Vanilla stuff. No fetishes. There's a tiny little bit of romance in there, but only just enough as to make things a tiny bit more plausible than just "ah what the heck, let's fuck even though I'm his ROOMMATE. Oopsy! I slipped and fell on your dick. Ha ha!"
Oh yeah, without the i-patch, most of this makes no sense whatsoever. Fortunately, the romance thing is kept to a minimum as to prevent things from getting disturbing. So you might want to apply the patch even if you otherwise don't like this particular genre. It feels like pretend-porn rather than an actual ROOMMATE love story.
About the humor, even though the dialogue isn't exactly hilarious, some of the scenes are really fucking funny. I don't want to spoil anything, but let's just say a couple of the scenes made me actually laugh out loud.
Also, no walkthrough needed. There's no way to lock yourself out of content. You can progress with every character, and if you reach a stopping point, you just switch to progressing a different one, and once you reach the required level of progress it unlocks further progress with other characters. The city map puts quest markers to indicate the characters that can be progressed, so you'll never get stuck.
The only downside is that (as of version 1.0b) the major decision near the end of the game doesn't actually affect much, as the rewards of those choices aren't actually implemented. The main story itself is fully finished though.
Oh, and before you even ask, this is a harem game. It's not even optional. The harem is mandatory.