Forbidden Castle

"If ye be the rightful ruler of Jasoom then find the fabled Jasoomian diamond and set right the evil deeds of the murky past!" With these words ringing in your ears you set for to the ancient castle to recover the fabled diamond, thereby re-establishing your rule. But the castle has sat unused for 1000 years and is now inhabited by giants, serpents, spiders and the mysterious loathsome blobs! You enter and the only known access is sealed behind you by your evil cousin Hogarth, usurper to the throne. Your goal, find the diamond and an exit before your energy runs out. It's a task surmountable only by a true ruler!!