As the name suggests, Castle Of Illusion HD is an attractive and fairly faithful adaptation of the legendary platformer. I say "fairly" because it introduces some 3D sections -- heresy! -- yet they work well and the package reminds us why we fell in love with gaming back in the day without cracking the rose-tinted specs. GetGames' cheap £2.49 price is the de-facto "deal" level, but still worth a go.
Thanks to jaystan @ HUKD!