First, two minor bugs:
-The Karen advancements don't seem to actually be enforcing the Abby level requirements.
-This causes another issue where if you go to the store in the afternoon with Abby at L3 and Karen at >= 20 affection, the new background images don't load. You get the Karen advancement scene, but it's either a black background, or whatever the previous background was if you were already at the store when it ticks over into afternoon. Fixing the first issue should fix this (by making it an unreachable state), I mention it in case someone else reports the issue, so you don't have to spend time searching on it.
-During the stage 4 Karen event, when Karen is riding the MC on the floor, there are frames of the animations where the MC flickers. It seems to be only at the start of the loop, and it's on all three of the reverse cowgirl animations. When it happens, there's a flicker of shadow on the ground that then vanishes, so my guess is that the shadow is being applied to the entire MC, and then simply overwritten by lighting effects of later frames.
Separately, feedback:
It would be nice if the later Abby/Karen advancements (and really, *all* advancement vignettes) were manually triggered, like the dates for Abby earlier in her transformation. With many characters having at least 6 or so unique talk options, as well as level-specific sex scenes, it's incredibly easy to level their affection so fast that you miss content.
Regardless, the game is a fun romp, and I'm looking forward to seeing where else it goes.