I specifically played two worlds during my demo, with the intent to focus on two of the new game mechanics in SMG2: the first being the drill bit power-up, which quickly wowed me with the nifty new level designs it has inspired; and the second being Mario's lizard pal Yoshi, who really is a space-faring plumber's best friend.
First, I was off to the aptly-named Spin-Dig galaxy to take the drill for a ... spin. (Hear that? It was me ducking.) Using this device, Mario can drill straight through the game's spherical worlds (and even some flat ones), a mechanic best demonstrated when I used it to reach a Launch Star perched atop an otherwise unreachable summit. To get to it, I had to drill in just the right spot, which sent me spiraling up through a tower of sand on the flip-side of the world. Once there, a few steps to the right and another use of the drill took me back through the world and up to my destination. Tricky, but very satisfying.
At the end of this stage, I went up against a two-legged robot straddling a wheel-shaped circular world. It launched drill robots at me, which I stomped, but there was no getting past its legs ... or was there? The robo-boss soon gave away its weak point: by waiting for its glass-domed, star-containing head to rotate around, I could then line up and drill all the way through the planetoid, popping out the other side and cracking the glass with my drill bit. The robot was soon vanquished.
Hopping over to another galaxy -- this one featuring "2D" gameplay akin to the kind that sometimes appeared in the first SMG -- I whacked a familiar green-spotted egg to free Yoshi. Hopping on his back added a subtle yet hallmark bongo beat to the soundtrack, and I quickly made with using his tongue to pull in enemies and power-ups. Controlling Yoshi worked really well; like with Mario, moving around is accomplished using the Nunchuk's analog stick. The Wiimote pointer is used to "aim" Yoshi's tongue, with the B-trigger making it dart out. I had him eat a fruit that made him blow up like a balloon, floating upwards by means of air escaping his mouth. Pressing the big A-button made him hold his breath, though the air meter still depleted (albeit more slowly). In this level, strategic swallowing of said fruit was necessary -- as one wore off, I had to snap up another in mid-air to keep from plummeting to the ground.
A boss fight in this world let me use Yoshi's penchant for spitting back what he's swallowed to my advantage. Another metal monstrosity, this giant enemy launched Bullet Bills at me, which I promptly had Yoshi gobble up and spit right back at it. I kind of regret not trying the same trick on the Hammer Brothers I'd encountered earlier, to see if I could perform a "return to sender" on their menacing mallets.
All in all, the segments of Super Mario Galaxy 2 I played felt, looked and sounded just like the original game -- with a few neat new tricks. I don't know about you, but that's just fine by me.