Gnasty Gnorc is the final boss in Spyro the Dragon. This is the only boss that has its own dedicated level and you won't find any dragon here. This means that if you lose you will have to start the level from the beginning.
At the beginning you will have to get the keys to the gate. To do this, head to the passage where the thief is. The thief holds the key in his hand. He moves around the circle and you will chase him until you catch him.
Once you have done this, you will be able to open the door opposite the gate on which Gnasty Gnorc stands. There you will find another thief. This time with the right key. You will have to catch him. Be careful, because the road along which you chase him is no longer a tunnel. You can fall into the water and start again.
Once you have obtained the key, go to the gate. It will open and Gnasty Gnorc will start running away. You must chase him until you are able to attack him when he stops in the designated circle. When you succeed another tunnel will open. Your opponent will escape using it.
Time is a key factor here. You have to cross all the platforms before they are completely hidden. If you do this you will be able to inflict a final blow on Gnasty Gnorc.