I would never get discouraged from such detailed feedback, quite the opposite, I really appreciate it.
A lot of these problems are going to be solved over time, this is an early alpha with a lot of missing polish. Many systems are there, but most of them need to be polished. There's still a lot of missing pieces, and so a lot of what you are talking about is already planned to be adjusted. But I can be a bit more specific if it helps:
1) Save System - manual saves are coming, right now the game saves at the start of each day, but this won't always be the case.
2)Balance stuff - the speed at which stats increase / decrease, the progression of events, etc - this is all subject to change. The game will take place over 4 seasns, I've got most of the available gameplay crammed into 90 days and I want people to be able to play within that space. When i release the next season you will immediately see how things will have more room to breathe.
3)UI Stuff - The UI has already changed a bunch of times in updates, the next update has different UI again. None of this is final, and I'm constantly iterating. People have given a lot of feedback (thank you everybody, you're awesome) and I'm very much listening. Just nothing happens over night - but I'm trying to address people's concerns while working through my own list of features.
4)Tutorials - of course I understand the need for these, but it'll be a bit before they show up in earnest. The game is very much incomplete when it comes to features, and making tutorials eats up my dev time. I'm not going to make tutorials until the features are in a more finalized state. I'll say here what I've said to many - there is no fail state in the game, don't worry about playing perfectly, just allow yourself to trial and error your way through for now. I promise some nice tutorials will find their way in eventually (especially for combat).
5)Knocking on door / Barging in. These are two different ways of progressing lucy's events. Barging in is not the primary way, knocking is. But both are a bit underbaked right now, so both will get some love in the coming updates.
6)A bunch of the bugs you listed are the result of incomplete features, or, just bugs. Thanks for posting them. The funniest one you listed is Lucy's missing arm in the handjob scene, I took a look and laughed out loud - yeah, the art didn't export correctly and absolutely there's a missing limb. I'll get that fixed for the next update haha.
7)We've got a discord server coming for feedback and whatnot. It's almost ready, and I'll post a link here and in game when it's up.
Thanks again for the kind words and feedback, it's very helpful! I hope you continue to enjoy the game, I've got a lot more coming.