Excellent game, I started playing it already when it was just posted last year, and spent 2d ingame playtime to finish both the starting and the science island (after waiting for it to be put into the game), then I mined everything on both islands and faced the boss on the science island, which wasn't fightable at that time.
Then I somehow messed up, erased my temporary internet data and my game progress along with it. I never uploaded it somewhere, so there was no way to restore it, but that doesn't stop me from doing it all again, especially with a new island and lots of new gadgets and mechanics to experiment with! :D
I noticed a bug though. (Spoiler alert)
When on the magic island, if I land with my dragon on one of the tiny floating platforms above the island (the ones with yetis on it) and I get off the dragon and dig through the ground, I fall down onto the island, unable to get back. My dragon stays on the platform, out of reach now, there's no other way for me to get up there (got no flight armor or whatever there might be) and I'm stuck on the island, unable to get to the other one for hatching and raising a new adult dragon. Luckily I didn't save after that incident and reloaded the file before that happened. Dunno if other players will be just as smart, if not they might get themselves stuck like that for real and have to restart the game. Ouch.
That's why I would recommend adding a "call dragon" function at the left edge of the island, that resets him to his usual position there. Could safe a poor soul from restarting everything.
If there actually was another way to get there, I didn't see it and it would be good to get it pointed out in such a situation (like after falling down from a platform the first time, or maybe even while landing on it).
Nethertheless a brilliant game, and I will definitely regain my progress on the 2 first islands, additionally to completing the third one as well and also mining everything there too, defeating all bosses I can find and finishing all quests ;)