Castle of Illusion has been relaunched and this is a good price for this entertaining and gorgeous game.
If you rather pay in AUD directly you can get it for a few cents more at Fanatical.
From the website:
Mickey Mouse returns to star in Castle of Illusion, a fantastical reimagining of the Sega Genesis classic. With all-new HD graphics and gameplay, Castle of Illusion brings Mickey and his world to life in this magical Disney adventure! When the evil witch Mizrabel kidnaps Minnie, it’s up to Mickey to brave the dangers of the Castle of Illusion to rescue Minnie. Gather your courage and traverse enchanted forests, take on hordes of rebellious toys and navigate mazes of living books. Play as Mickey and save Minnie from Mizrabel’s evil clutches!