Hear the Sega Scream
Tap A as the game boots. When the Sega logo appears, you will hear the famous "Sega!" scream instead of the normal music.

the Love Shockers
How to unlock: You need to beat the Shibuya-Cho levels, getting a Jet ranking.

Noise Tanks
How to unlock: You need to beat the Benten-Cho levels, getting a Jet ranking.

Prof. K
How to unlock: If you want to play as Prof. K, beat the game and save.

Poison Jam
How to unlock: You need to beat the Kogane-Cho levels, getting a Jet ranking.