Enable the "Invincible Aircraft" control setting. Then, enter
one of the following codes during flight to activate the cheats:
 
Code                   Result
----------------------------------------------
[Ctrl] + [Tab]       - Add 500 feet to altitude
[Ctrl] + [Tab] + S   - Slow motion mode
[Ctrl] + [Tab] + X   - Enable joystick

During gameplay Press "P" For pause.

Effect                 Code
------------------------------
+1life/9lives        - LF1/LF9
Can jump/Can't Jump  - AJU/AJD
Can't Jump(Fly Down) - JDN
Fly                  - FUS 
Go to next level     - New
keep Jumping         - JUS
Kill 1 enemy         - Kil
Kill enemies         - All
Slow 10/Slow 30      - SL1/SL3
Speed 10/Speed 30    - SP1/SP3
Stop 10/Stop30       - ST1/ST3
Walk (Fly Down)      - FDN