If the demo is an accurate representation of the game, I feel you should not get a refund.
Blizz-o-vision started doing this with Diablo 3. IMHO, the game was EXACTLY like the demo. There were tons of things awry and missing, but it was accurate.
Now this game might be another story. I cannot make a claim since I have played neither the demo nor the full versions.
The slope is slippery.
The good side is, if game companies are dumb enough to give refunds, they may be more akin to making sure their games are at least as advertised.
Demo's used to always just be the first 10-40 minutes of the game. I'm not sure why they stopped doing this TBH. Then again, I spent a large part of the PC game toddler years just playing demo's except for a few games. So maybe that's why....