Stargate.

 No.  Code  Effect
   1  ABEA-EADY  Start with 0 grenades
   2  NPEA-EADY  Start with 99 grenades
   3  AAEA-EAFG  Infinite grenades
   4  AKEA-EADW  Start with 3 lives
   5  NPEA-EADW  Start with 99 lives
   6  AA5A-EAH6  Infinite lives
   7  NPEA-EADT  Start with 99 continues
   8  AA5T-EAD2  Infinite continues
   9  NPEA-EAD0  Start with 99 alien grenades
 10  AAEA-EAE2  Infinite alien grenades
 11  C27A-CA6W + BT7T-CA3E    Protects against most enemies
 12  AA5T-EAC4  Don't lose energy when you fall off screen
 13  ACHT-CAHL  Protection against floor spikes
 14  A0NA-AAHC  Pick up five mission objectives for each 1 you get  
 15  ACBT-CAHE  Extra life worth nothing
 16  ALBT-CAHE  Extra life worth 2
 17  ACBT-CAGR  Energy icon does nothing
 18  JCBT-CGGR  Energy icon restores energy to full
 19  ADXT-CAGA  Machine gun does not heat up
 20  LDXT-CAGA  Machine gun heats up quicker
 21  RHXT-C61A  Machine gun cools off instantly
 22  AC0T-AAG0  Invincible after you get hit