Firehawk by Codemasters/Camerica has a few Easter Eggs built-in, such as a Dizzy demo. Score enough to get onto the Top 10 highscore,
around 40.000 points. When you die in the game enter your name as "DIZZY" and you'll see a rolling demo from Fantastic Adventures of Dizzy.
To read some rather useless messages, enter "CAMERICA" or "MIG 29" instead of "DIZZY".
If you'd like to Warp to level 2, hold dowm A while pressing Start on the titlescreen.