Jasper by Adam Davidson & Andrew Pollard
Head Over Heels was released, um, a while ago. Around about 1987 if I recall correctly and it was immediately praised in the press as being quite the bestest thing ever. Not only was it a huge game for it's time, it also had great graphics and was very addictive - if somewhat punishing in its difficulty level. The variety in the locations was amazing and the challenges brilliantly designed. Quite rightly it was awarded with pretty much every accolade that could be bestowed upon it by the various magazines. Even today it still stands as a brilliantly designed title and has never really been bettered in the isometric adventure genre.