As far as the single-player campaign goes, things will remain largely unchanged. There will, however, be a few small tweaks to the formula. This time around you'll be able to revisit campaigns after you complete them. So if you want to go back and play any optional missions or battle puzzles you missed the first time around, that option is now available. However, Vella was coy as to whether or not there will be any actual new content in the single-player mode, saying simply "we'll see."
But even without any additional single-player content, Clash HD still features enough new that fans of the original will probably want to do the dreaded double-dip anyways. The high-def visuals look to be worth the price of entry alone, but with the balancing issues ironed out and an online competitive mode, this remake could end up being even more addictive then the original. And that's saying something. Expect to see the game hitting both XBLA and PSN sometime this Summer.