Hey, it's been a while! Two years already... Wow.
I recently played through the demo actually on the official website and realized that it hasn't aged well... It was released 3 years ago, and a lot of things have changed since then. Therefore, a new demo is now available!
This new demo includes 3 of the main missions of the game (the 1st, 6th and 12th ones) on 3 different worlds, and the first 3 training missions. It is a huge demo with a lot of things to do, missions you can play in different ways, secrets... It will take you a few hours if you're willing to see everything.
And if you're wondering what it looks like, here is a gameplay video of one of the missions in the demo:
Don't hesitate to bring some feedback, and to share this demo around; the game isn't mentioned that much, so a little help would be more than welcome!