Sega's House of the Dead 2 & 3 Return actually has something new to offer, other than "being on the Wii" and "different crosshair shapes!" Sega has added an Extreme Mode to House of the Dead 3, which adds new player abilities and ramps up the difficulty -- perhaps to an extreme degree?
Enemies move more quickly and the shotgun's blast radius is smaller. But in order to balance the increased difficulty, the player has been given a new attack. You can now press A to perform a melee attack that not only knocks enemies away, but also blocks attacks and projectiles.