Rolling Thunder 2.

 No.  Code  Effect
With Codes 1 thru 13 the blue box display looks funny until you have 4 or less hit points left.
   1  ABMA-AAHN  Start with 1 hit point--player 1
   2  AKMA-AAHN  Start with 3 hit points--player 1
   3  AVMA-AAHN  Start with 5 hit points--player 1
   4  A3MA-AAHN  Start with 7 hit points--player 1
   5  BBMA-AAHN  Start with 9 hit points--player 1
   6  B3MA-AAHN  Start with 15 hit points--player 1
   7  ABMT-AAAR  Start with 1 hit point--player 2
   8  AKMT-AAAR  Start with 3 hit points--player 2
   9  AVMT-AAAR  Start with 5 hit points--player 2
 10  A3MT-AAAR  Start with 7 hit points--player 2
 11  BBMT-AAAR  Start with 9 hit points--player 2
 12  B3MT-AAAR  Start with 15 hit points--player 2
 13  FDJA-AEZ6  Almost invincible--both players
 14  CBLA-AAFJ  Start with 10 pistol shots--player 1
 15  EBLA-AAFJ  Start with 20 pistol shots--player 1
 16  GBLA-AAFJ  Start with 30 pistol shots--player 1
 17  NBLA-AAFJ  Start with 60 pistol shots--player 1
 18  TBLA-AAFJ  Start with 80 pistol shots--player 1
 19  ABLA-ACFJ  Start with 100 pistol shots--player 1
 20  XFLA-AWFJ  Start with 999 pistol shots--player 1
 21  CBLA-AAFT  Start with 10 pistol shots--player 2
 22  EBLA-AAFT  Start with 20 pistol shots--player 2
 23  GBLA-AAFT  Start with 30 pistol shots--player 2
 24  NBLA-AAFT  Start with 60 pistol shots--player 2
 25  TBLA-AAFT  Start with 80 pistol shots--player 2
 26  ABLA-ACFT  Start with 100 pistol shots--player 2
 27  XFLA-AWFT  Start with 999 pistol shots--player 2
 28  CBLA-AAFL  Start with 10 machine gun shots--player 1
 29  EBLA-AAFL  Start with 20 machine gun shots--player 1
 30  GBLA-AAFL  Start with 30 machine gun shots--player 1
 31  JBLA-AAFL  Start with 40 machine gun shots--player 1
 32  NBLA-AAFL  Start with 60 machine gun shots--player 1
 33  TBLA-AAFL  Start with 80 machine gun shots--player 1
 34  ABLA-ACFL  Start with 100 machine gun shots--player 1
 35  XFLA-AWFL  Start with 999 machine gun shots--player 1
 36  CBLA-AAFW  Start with 10 machine gun shots--player 2
 37  EBLA-AAFW  Start with 20 machine gun shots--player 2
 38  GBLA-AAFW  Start with 30 machine gun shots--player 2
 39  JBLA-AAFW  Start with 40 machine gun shots--player 2
 40  NBLA-AAFW  Start with 60 machine gun shots--player 2
 41  TBLA-AAFW  Start with 80 machine gun shots--player 2
 42  ABLA-ACFW  Start with 100 machine gun shots--player 2
 43  XFLA-AWFW  Start with 999 machine gun shots instead of 0--player 2
 44  ADYT-BE9N  Infinite pistol and machine gun shots--both players
Codes 45 thru 61 can make the flame thrower shots look funny.
 45  CBLA-AAF2  Start with 10 flame thrower shots--player 1
 46  EBLA-AAF2  Start with 20 flame thrower shots--player 1
 47  GBLA-AAF2  Start with 30 flame thrower shots--player 1
 48  JBLA-AAF2  Start with 40 flame thrower shots--player 1
 49  NBLA-AAF2  Start with 60 flame thrower shots--player 1
 50  TBLA-AAF2  Start with 80 flame thrower shots--player 1
 51  ABLA-ACF2  Start with 100 flame thrower shots--player 1
 52  XFLA-AWF2  Start with 999 flame thrower shots--player 1
 53  CBLA-AAF8  Start with 10 flame thrower shots--player 2
 54  EBLA-AAF8  Start with 20 flame thrower shots--player 2
 55  GBLA-AAF8  Start with 30 flame thrower shots--player 2
 56  JBLA-AAF8  Start with 40 flame thrower shots--player 2
 57  NBLA-AAF8  Start with 60 flame thrower shots--player 2
 58  TBLA-AAF8  Start with 80 flame thrower shots--player 2
 59  ABLA-ACF8  Start with 100 flame thrower shots--player 2
 60  XFLA-AWF8  Start with 999 flame thrower shots--player 2
 61  ADZA-BE70  Infinite flame thrower and shot cluster shots--both players
With Codes 62 and 63, special weapon shots can look funny
and may have different degrees of effectiveness, depending on the round.
 62  AXST-ANAE  Make flame thrower special weapon in round 5, instead of shot cluster
 (standing shots only--you still get shot cluster when you crouch)
 63  SXSA-B4SY
 + A5SA-ANH0  
 Make shot cluster special weapon in all rounds instead of only in round 5  
 (standing shots only--you still get flame thrower when you crouch)
 64  PZTT-AADT  Timer runs at 1/10 normal speed
 65  VBTT-AADT  Timer runs at 1/8 normal speed
 66  CFTT-ACDT  Timer runs at 1/4 normal speed
 67  PVTT-ACDT  Timer runs at 1/3 normal speed
 68  EKTT-AEDT  Timer runs at 1/2 normal speed
 69  VBTT-ATDT  Timer runs at 2x normal speed
 70  3VTT-A2DT  Timer runs at 3x normal speed
 71  CBTT-BCDT  Timer runs at 4x normal speed
 72  EBTT-AEMT  Timer runs at 8x normal speed
 73  ZBTT-AYMT  Timer runs at 10x normal speed
 74  BFTT-AF56  Infinite time
 75  ABCA-AAF8  Start with 1 life instead of 3--player 1
 76  AFCA-AAF8  Start with 2 lives--player 1
 77  AVCA-AAF8  Start with 5 lives--player 1
 78  A3CA-AAF8  Start with 7 lives--player 1
 79  BBCA-AAF8  Start with 9 lives--player 1
 80  B3CA-AAF8  Start with 15 lives--player 1
 81  GFCA-AAF8  Start with 50 lives--player 1
 82  ABCA-BE7Y  Start with 1 life--player 2
 83  AFCA-BE7Y  Start with 2 lives--player 2
 84  AVCA-BE7Y  Start with 5 lives--player 2
 85  A3CA-BE7Y  Start with 7 lives--player 2
 86  BBCA-BE7Y  Start with 9 lives--player 2
 87  B3CA-BE7Y  Start with 15 lives--player 2
 88  GFCA-BE7Y  Start with 50 lives--player 2
 89  AMWT-AA5N  Infinite lives--both players
 90  SA7T-BEZA  Start at round 2
 91  SA7T-BJZA  Start at round 3
 92  SA7T-BNZA  Start at round 4
 93  SA7T-BTZA  Start at round 5
 94  SA7T-BYZA  Start at round 6
 95  SA7T-B2ZA  Start at round 7
 96  SA7T-B6ZA  Start at round 8
 97  SA7T-BAZA  Start at round 9