This was made in just six months?! What the hell? Please tell me you're still working on this, I love this and want to see more of it.
With that said, dunno if you've fixed any of this, but the demo has some issues:
1) Crashes randomly on full screen. Rarer crashes in windowed mode. I have the font installed and the RTP as well so I've no clue what this is, it does not give me an error.
2) If, after the cutscene in Jadan Village, you immediately go back, a sprite of Eirik will just stay near the exit. 
3) Very minor, but collision bug. 
4) Necklace quest is still listed as active despite being finished.
5) Dunno how to explain, but occasionally the music will loudly stutter (kind of similar to the waterfall sound in Jadan Village). Mainly during battle. Happens everywhere.
6) This is more of a request, but there should be a sort of manual for tutorials. Unless I'm not seeing it I want to sometimes revisit the tutorials for mechanics I forget like the ATB battle start states
7) Sound effects are very loud in comparison to the music. Please make it possible to edit music and SFX volume
8) In Marine Pipes #2, the lever surrounded by water will either disable the barriers without a Lever Rod, or its sprite is bugged
9) In Mirstone Village, the non-interactable NPCs may walk above tree sprites if they're near the road.
10) Both the hammer and recipe become different tiles when interacted with, and the bucket has no collision.
10.1) Crates on the other side of the bridge have no collision.
11) If you enter the Secret Room in Jadan Caves with a full party of 3 and exit it, you will get softlocked
12) Marine Pipes #1 cutscene can be retriggered on the northern exit. It also softlocks you.
I know this demo has been published 2 years ago and I wasn't able to find anything on this project further, but I hope you're working on it! I would love to see more of it (and whatever your main project is!)