Alt modes. Megatron's transformation consists of his limbs dislocating and rotating around before his 'wings' close around him, making a neat pistol of fictional make. His trigger moves and makes a rather satisfying click when you pull it, and you can actually look through his sights, which have crosshairs in them (though you really can't see a whole lot). You can keep his toes and heel extended on his 'handle' to make him stand up. I will never not hate US gun laws for forcing the stupid orange caps on him; I'm considering painting both gold to match the other accents on his body (why not? I don't plan on carrying him around in public).
Prime turns into a truck as usual, though now he's a cab-over truck with a wind vane (made from his big blaster; I like the big Autobot face printed on it) on top. With the knees flipped the right way around, they now fold a bit more neatly against his bed, though he doesn't have a trailer and has no actual way of connecting one to him anyway. His double-barreled shotgun spits and becomes his smokestacks. I'm...very confused by what the clear blue bits are supposed to be; they're what his annoying arm kibble unfolds into, and while they're clearly supposed to be the sides of his cab (and are painted normally on other releases of this mold), I'm not sure why they're clear blue here. His transformation is pretty straightforward, except for the part where you rotate his upper torso (right under his windshield pectorals) instead of rotating his waist.
They're not horrible toys - clearly dated, and not the best likenesses of the characters they're supposed to represent - but they're kinda neat, and I really like having an official 'gun Megatron' for the first time ever (even if he's not going to be 'Megatron' once I decide on a name for him - I'm seeing him as being more of an unhinged pyromaniac, along the lines of BW Inferno); as a bonus, he fits perfectly into my Black Zarak's claws, so he's being used as his main gun right now.