SNK Playmore has been very keen on mobile games, and recently they released the tower defense game Metal Slug Defense, bringing the old and glorious franchise to iOS and Android.

Something else seems to be brewing, as the developer now registered "Metal Slug Attack" with the Japanese Trademark and Patent Office.

Interestingly, the trademark information does not include the term "mobile game," which is often specified in Japanese trademarks.

Will it be just another mobile game, despite the fact that Metal Slug Defense was released just this year, or something else entirely? We'll have to wait and see.