Mediocre in every way. I think Grandma's House shows that the key to making a successful profitable AVN is just to have consistent, regular updates. In that area, the dev certainly deserves kudos. Dude has been pounding out monthly updates for most of a decade.
Unfortunately, he's been pouring all the energy and work into a repetitive, absurdist, pointless game. Let's run through it together.
Visuals: 5/10
Old, dated. Compared to shining stars like Babysitters or APM, Grandma's House is just average. I will say, however, that the dev included every imaginable body type, from flat-chested girls to comically busty women; jail bait to geriatric; black, white, every-possible-ethnicity; all hair colors; even midgets.
Love interests: 2/10
Every woman that appears on screen is a love interest. Not a single one ever denies the MC or plays hard to get. All are instantaneously attracted to him, often to the point of struggling to restrain themselves. It's pathetic.
Story: 1/10
By the time i got to the end of this VN, i genuinely needed a minute or two to try and remember what, if any, plot there was. There's a bit here and there about MC's family, many of the LIs have some connection to his past (his buddy's sister/mom, his grandma's friend, etc.), but really, there's no point. It's just the story of Chad Thundercock coming home from college and plowing every woman aged 18-90 in multiple countries.
None of the characters change based on your 'choices', all are still insanely in love with the MC. Here's a typical encounter (paraphrased for length):
MC: hey lady, i'm like, so in love with you. hope you get preggo!
MILF lady: for realz, super-serious, you're the most important thing in my life since i met you last week!
MILF's daughter: O-M-G mom, you're banging MC too? And he knocked you up?
MILF lady: for realz, Daughter. MC is your new daddy.
MILF's daughter: But mom, MC knocked me up and has been banging me since my 18th birthday!
MILF lady: that's like, super awesome! woohoo! *threesome ensues*
I know. So realistic it's like the dev held up a mirror to my life....
Choices/Interactivity: 1/10
No choices make any impact on the plot (mostly because there is no plot). All of the characters are entirely one-dimensional - this one is a submissive, this one like facials, this one likes raceplay, this one likes taboo. They aren't characters, they are fetishes personified. Not a single character drives any sort of cohesive plot. The MC is simply a penis on legs.
Overall: 2/10
I guess I'm just not the target audience for this sort of game. It's insultingly simple, with zero effort put in to plot, characters, dialogue, setting. There are high-quality images of naked women on the internet. I don't read/play AVNs for the low-quality Daz images, i read them for the story. And this has none.