Glad you dig the concept, Ty was a fun PS2 game I personally played a good amount of back in the day, so I'm happy the zany Australian aesthetic bleeds through a bit.
In terms of the gems, we have tossed around the idea of having them be used as currency, but as it currently stands we're planning on implementing unlockables based off of the treasure you can get in each level, which is the reward you get for getting all gems.
We have noticed for a good amount of players the boomerang can be a little bit unwieldy when it comes to "sticking" to the fan, so we will experiment with working on the magnetism and trying to find a good sweet spot in that regard.
Thanks a ton for trying out our demo, we'll try our best to make it as fun as possible!