DLC that makes me feel cheated:

Deatsmiles Black Label DLC - 1400 JP points, available for free on Platinum Hits

Mushihimesama Futari Black Label DLC - 1400 JP points, available for free on Platinum Hits

Dodonpachi Daifukkatsu Black Label DLC - 1400 JP points, released retail disc Dodonpachi Daifukkatsu Black Label 2 months after Dodonpachi Daifukkatsu, and Black Label DLC released at the same time with the retail Black Label version.