Board Thread:General Discussion/@comment-29855659-20170630205901/@comment-31371628-20170711173033

To part of your 4th question:

Well, it's hinted/explained (I haven't played Undertale for a while) by Flowey that he SAVEs over your own death, and then reload the SAVE. I think Flowey would know when you quit, and reloaded the SAVE to make sure you listen to his speech. Suggesting that Flowey has some meta-knowledge, he could assume that you had to do something, and so he could assume from there that you forgot about his speech, and so he says it again just in case, and pretends that he didn't give you the speech before. (Then again, this is a video game, so this is most likely something Toby didn't see coming.)

And to answer your 2nd and 3rd question: "Determination" is the will to live. It could be that Undyne and the Amalgamates refuse to die, and while they can not SAVE, we don't know if that's determination's only power. The fact that Frisk cannot die in the final fight against Asriel doesn't have to be related to SAVEing, as there is no connection between the two other then determinaiton. Undyne and the Amalgamates could have refused to die, and continue to live (for a little), and/or become more powerful before dying.

The first question I cannot answer. Undertale doesn't explain a lot.