Tbf they added stuff to make harder levels easier to pass with items in the shop. Plus if you fail that just means you need to improve and you only lose if you complete fail a note aka hitting the wrong key or just not pressing it at all 4 times in a row without items. The timing is very forgiving too as i'm sure you noticed. Theres 4 degrees of hitting a note that doesnt impact you negetavily, Perfect, great, nice and meh. Considering all that i dont think the game is unfair if you fail cuz of hitting the wrong key or not pressing anything. (I'm not saying you're bad i'm just saying in my opinion the game is already fair enough and doesnt need to be any easier)
I'm not really asking for an overall decrease in difficulty, but rather a smoother transition between failure and success. I was eventually able to win all the levels. But I jumped directly from failing outright to getting 4 stars, and that's what felt weird. I actually think it might make sense to make it harder overall; but something feels wrong about just a slight difference in timing for half a dozen notes being the difference between failure and near-total success.
I think it might be the fact that Beat Banger focuses so heavily on successive notes---it's missing several in a row that makes you fail. I think I would prefer if it were a larger absolute number of missed notes, like "you can't miss more than 50" rather than "you can't miss more than 5 in a row".
To see what I mean, compare SpunkStock. Unless you specifically get the Doom modifier or several stacked Whip modifiers, you can miss several notes in a row without failing. You won't get the coveted SS or even S ratings, but you can still make it through the scene.
Overall I like Beat Banger better than SpunkStock; I particularly love that the beats you trigger are actually thrusts in the sex scene. But the difficulty curve in SpunkStock feels smoother, without the jarring leap from "you suck" to "you're amazing".
A different way to make successive notes important would be for the "Combo" count to actually do something, which as far as I can tell it does not. Some sort of bonus score multiplier you get at certain levels of combo (or even literally just +1% score for each beat per combo, so a 127 combo is +127% points) would provide incentive to never miss a beat without making you suddenly fail because there's one fast section of a song you're bad at.
I did mention there are items that can give you more hearts aka more chances to miss notes without insta loosing its in the shop and cost 500 and i believe you can get 3 so you could miss 6 in a row and still be fine. As for the difficulty curve it is rather big difficulty curve ill admit but thats the thing with beat games, you adapt. If you dont want to spend the money you get thats kinda on you. But i get it my man.