Personally I have no problem whatsoever with the game... except some of the missions are much harder than the original, which is a good thing. Things like you'll fight helicopters, and then fight a tank, and then fight more helicopters, and then fight another tank.

Boss fights are still very exciting... for instance, there is this really big guy with gattling guns, a guy packed with missile launchers (or some WEAPON OF MASS DESTRUCTION?), some robots, and some really large biomechanical creature... and more.

By all means buy the game.

Here's a picture of the three characters:
http://newodin.gamer.com.tw/PIC/odin/screen/006207a.jpg