A new trailer for Sonic the Hedgehog 4: Episode 2 has arrived, showing off some gameplay footage and teasing the return of Metal Sonic--at least for those who've purchased Episode 1 as well. Four exclusive levels featuring the blue hero's metallic counterpart will be available to anyone who buys both episodes.

The four Metal Sonic bonus levels--called "Episode Metal"--will help bridge the narrative gap between Sonic CD and Sonic 4. In the new trailer that's been released, you can also see that Sonic the Hedgehog 4: Episode 2 will also sport the "Lock-On" functionality that debuted in Sonic & Knuckles.

Sonic the Hedgehog 4: Episode 2 hits the PlayStation Network on May 15, and Xbox Live Arcade a day later in North America. PC and iOS versions are expected to arrive sometime in May as well, with the Android version following in June.