In Resident Evil: Umbrella Chronicles you play through the previous Resident Evil games in first person mode. Use your wii mote like a gun to shoot and kill hundreds of zombies.
The graphics vary from being really good to rather mediocre. This is because it seems like Capcom reused some of the old graphics from previous Resident Evil games. It isn't TOO bad but it is noticable if you look hard enough.
I have not played it with the Wii Zapper.. but I do know with the Wii Remote it is pretty solid. This game tends to be more fun with a second player however. If I were to describe gameplay to a fellow gamer I would say "It is like an shooting game at an arcade, except more technical." As in to unlock everything you will have to pay good attention to what you are doing on screen.
The music and voiceovers are decent. You will either love or hate Wesker's voice. The music sounds very reminiscent of old Resident Evil games.
It would probably take you around 10-20 hours to complete the entire game. It really depends on how many times you need to run through the stages to unlock everything.
I recommend playing this game multiplayer. It seems to increase the amount of fun you have quite a bit.
I'm not really sure this game is worth paying 49.99 for. Maybe for the 'hard core' Resident Evil player. I would wait until this one drops to 29.99 or less.