Contra 4 Nintendo DS Cheats

Weapons (Normal or Hard mode)
Enter Up, Up, Down, Down, Left, Right Left, Right, B, A, Start in the pause menu to upgrade your weapons fully.

30 Lives in Original Contra
Press Up, Up, Down, Down, Left, Right Left, Right, Y, B at the start screen of the original Contra game, then press start to begin the game with 30 lives.

10 Extra Men
At the title screen for Super C enter: Right, Left, Down, Up, B, and then Y.

Challenge Mode
Complete the game on any difficulty to unlock Challenge Mode. This includes Easy.
Unlockable: - How to Unlock:
Contra (NES) - Complete 4 challenges in Challenge Mode
Contra 4 DS Promotional Comics - Beat 32 challenges in Challenge Mode
Contra III Comic - Beat 24 challenges in challenge mode
Extras Museum and Sound Gallory - Beat 40 challenges in Challenge Mode
Jimbo & Sully - Beat 36 challenges in Challenge Mode
Lucia (Character) - Beat 20 challenges in challenge mode
Nobuya Nakazato Interview - Beat 16 challenges in challenge mode
Probotector - Complete 12 challenges in Challenge Mode
Sheena Etranzi - Complete 28 challenges in Challenge Mode
Super C (NES) - Complete 8 challenges in Challenge Mode

Alternate ending
Successfully complete the game under the Normal or Hard difficulty setting.

Alternate colors
Successfully complete the game. Press Up (2), Down (2), or X (2) at the character selection screen to choose one of three alternate colors.

99 lives
Lose a life precisely when you gain an extra life. You will now have 99 lives.