Since the game is currently just a teaser, I'll try to make the review short.
The good:
Art: Holy shit is the art in this game amazing (10/10). Its unique, detailed and high quality, what more could you want ?
Voice acting : it is a rare sight to see a game have voice acting in its earliest stages. Here, it is even more impressive since it is not only done very well, but the characters have southern accents fitting, both, the story and the setting.
Kinks: the game is not vanilla and thats great. By allowing extreme kinks, the writer is effectively free to introduce any fetish he/she wants in the future without limiting their ideas/story.
The bad:
Gameplay: in the current alpha demo the game play is of poor quality. Whilst the vast majority of the game is undoubtedly going to change , the core mechanics, in other games, often remain the same or similar when compared to their initial versions. I do hope this is not the case for My Breast Friend Sally. Currently the 2 existing quests require you to find items on the map, which effectively means scanning an area with your mouse until you click on the right spot (the spots are neither obvious nor big). To me, such gameplay is tedious at best and I sincerely hope that the way quests are done will be changed in the future to a more engaging approach.
Overall 4/5. The game definitely has potential but without careful considerations and potential re-works it could, instead of improving, worsen.
Edit: thankfully NTR wasn't the focus of the game but unfortunately they literally added 1-2 new scenes and said it was complete, so overall rating goes down from 4 to 2. Would not recommend.