Matthew Bowers’s review published on Letterboxd :
This is a weird, and not very good, movie. Peter MacNicol feels miscast as the lead, but then again, it's hard to say whether or not he's miscast since his character, and all the other characters for that matter, are so underwritten. There's an interesting moment with the love interest character Valerian which could be read as a trans coming-out story, and that's surprisingly affecting (I am cis, take this as you will), but the rest of the characters (& indeed, even the rest of the scenes with Valerian) are incredibly dull and lacking in any human motivation or spice whatsoever. Even the princess' moment of courage and sacrifice doesn't seem to come from anywhere, since we know so little about her to begin with. The entire script just feels very hastily thrown together, and the acting and the direction don't really do it any more favors.
As for the dragon effects: ugly design, decent puppetry, terrible compositing.