The list of bosses keeps growing
The formula is the same, but the characters have changed and there are a few addition. The Maverick Hunters are on the loose and have some Zero Parts that may be useful. Get them together and there may be a surprise.
The addition of the new element provides a little increased difficulty but not much.
The tell the truth, the game only provides a sequel with nearly the same exact formula. Fans of the series will probably enjoy the new set of bosses, but new gamers to the series will be able to get into the game. It may be a little easy overall, but it is fun to play and will entertain.