Collect all twenty blue gems to view a congratulations screen after the ending FMV sequence.
Blue gems
To get blue gems, Find the three red gems in any level. Then, win the bonus game at the end of the level and the Genie will reward you with a blue gem.
Defeating Bow Warriors
To kill the Bow Warriors found in Agrabah, hit them when they start spinning their bow.
Defeating minotaur guards
To kill the minotaur guards found in the pyramids, throw four flaming swords at them, then hit them with your sword.
Defeating minotaur warriors
To kill the minotaur warriors found in the pyramids, attack them when they start walking around you.
Defeating mummies
To kill the mummies in the pyramids, throw four flaming swords at them.
Defeating spiders and snakes
To kill spiders and snakes quicker, use the downward jab.
Defeating Spinners
To kill the Spinners found in Oasis, hit them when they put their swords by their sides.
General tips
Until it is safe to attack, block the enemies attacks.
Always keep some apples/rocks/flaming swords/etc. on you. You never know when you might need them.
Try to get all the Genie Tokens in order to get lives/continues/full health, etc. at the end of the level.