Invincibility:
Enter DEATHWISH as a password.

Unlimited ammunition:
Enter BIGPOCKET as a password.

All weapons:
Enter TOOLEDUP as a password.

One shot kills:
Enter OOHSTOPIT as a password.

Rapid fire for shotgun:
Enter MYBIGUN as a password.

Extra explosion damage:
Enter ACMEBANGS as a password.

Enemies do not move:
Enter COLDFEET as a password.

Invisible mode:
Enter DOYOUCME as a password.

Alternate sounds when hit or killed:
Enter HORNBLOW as a password.

2	SMOKEY	RAVEN
3	BUTTERFLY	FIREFLY
4	COVEY	BULLDOG
5	TIGER	DRAGON
6	HORNET	LOUDMOUTH
7	LITTERBUG	STINGER
8	MUSTANG	NAIL
9	SPECTRE	ZORRO
10	NIMROD	XRAY
End	SPOOKY	REDDOG

Hint: Multi-player linkup:
You can link up a Game Boy Advance with Ecks vs. Sever and a Game Boy Advance with Ballistic: Ecks vs. Sever 2 and still play all the multi-payer modes. The level combinations between the games are slightly glitched, but it still works.