Newly released today:
Metal Slug the horizontal shooter is making new grounds in the Sony PSP platform. The new game makes use of the wide screen to display some high color resolution graphics. You can use the LAN facilities and ask friends to participate in the war with you.
When you get a friend to join the frontiers with you, you'd be able to take care of enemies in different parts of the stages. Besides the main mission, there is a new combat school mode where you get to play with 70 weapons and learn warfare tactics under a tsundere beauty.