I actually picked this game up last Friday, but after a half hour of rather painful Wiimote play it became extremely obvious that the only way I was going to get any joy out of the game (after a half hour my wrist was suffering from a bad case of Wiimote arthritus) was to get a 3rd Party peripheral like the Perfect Shot.
While I was out today picking up Madworld, as it so happens that GS also happened to have a Perfect Shot. There being no GS near my home that carries them right now, I picked up the Perfect Shot as well. Good thing, too, because after a rather disappointing sports night I decided now was a good night to break in the Perfect Shot on House of the Dead: Overkill. Wow, what a difference the Perfect Shot makes in the game, as the game dramatically turned around for me from a stylish but painful and simplistic arcade shooter into a completely awesome light gun shooter. Seriously, the Perfect Shot fits my hand like a glove, and it feels just as good in practice as the old NES Zapper (only the Perfect Shot actually works consistently). Overkill is just plain fun, and I really appreciate that while it's a really short game (In just over an hour of play I've completed the first two levels and played the first again with more mutants), they've left plenty in there for you to do with lots of stuff to unlock via in-game achievements. Definitely the most fun I've had with a Wii game in ages, and with the Perfect Shot being such a vast improvement over the Wiimote for this kind of game...I might just pick up a used copy of Umbrella Chronicles and continue my old game. Accuracy is so much easier with a real gun trigger and steady grip...
For the sake of players who don't keep up on Wii peripherals, they really should have put a label on the game saying that the Perfect Shot is not only recommended for this game...it's absolutely required. The Wiimote is just not built well to handle fast-paced shooters that rely on the B button and quick Wiimote movement.