Grinding (a little bit is ok)
Not knowing what to do to progress the plot
Bad writing - both plot and dialogue
But also too much writing even if it is good - an example is Triple Ex. It's well written but the banter just goes on and on...
Ugly models.
For example, I keep hearing Light of My Life is a great game but I can't get myself to play it when the main LI's look like they have cerebral palsy.
NTR, excessive grind, tits so massive they have their own gravitational field, cocks the size of a leg and worst of all bad grammar, when I see bad grammar i just stop playing no matter how good the game is, it just triggers the fuck out of me
NTR, massive boobs, bad sandbox with lot of grinding with no clue on what to do, and bad translations. Bad animations.
Sometimes bad translations is so bad I just have to stop.
Low quality renders, especially jittery/short-looped animations
Lots of OK-looking games where the dialogue is so horrible it's not playable, lots of good-looking games with comic-sized genitals, and a few old games with small renders. Non-porn games - even indie - are often Unity 3D, not questionable 3DCG RenPy with even worse animations.
Also, seems like most games nowadays are pretty upfront with what to expect especially once some forum comments from others comes about. So it is easy to avoid surprises.
remakes,too big time periods between updates and especially when a game get to the most anticipated scenes after a long period.Like u gotta give the people something or else they ll also dont care about your game