not at all, even that game seems to go backwards instead of increasing content, necklace quest is one of the first quests you can make, and has different ways to get that necklace needed for quest... clue, in order to find a waterfall, follow water, grandpa as you say , if mean old pervert with amazing fighting skills you want to learn, is past waterfall on mornings as he says on day 2 , and still going south reach marsh where can find who found necklace on afternoon.. but she wants another (dont say what, but is another necklace , all girls love shiny things) you can buy one for 80 at armor store, find one on a chest in ada's room, and remember i got another somewhere else too..if i remember right, that's basically the end of the content. i played it months ago though(although, it looks like the game hasn't been updated since anyway).
game has some broken inventory, stuff for quest is counted to end them but is not given and still keeps on my inventory after completion, so still may sell some stuff you wont need later