Last month, Sony started re-releasing PlayStation 2 games as digital downloads in North America. This surprise announcement included the release of five titles: Ring of Red, Maximo: Ghosts to Glory, GrimGrimoire, God Hand, and Odin Sphere"‹.
Out of the five initial releases, Odin Sphere was the top selling title in October. Vanillaware's game was number 15 on the top 20 selling games from October 2011 sales chart. God Hand was the only other PS2 classic that made it on the list.
Other subsequent titles released under the "PlayStation 2 Classics" banner are Bloodrayne, Harvest Moon: Save the Homeland, Stuntman Ignition, and Full Spectrum Warrior. PlayStation 2 classics are $9.99 each on the PlayStation Store.
Source: PlayStation Blog