I bought this originally so my 5 year old grandson could haved a game he could play on our Wii. We have two guns, so pointing at the screen and shooting terrorists sounded like something he'd enjoy.
My 20yo son and I decided to 'test' it *coughs* and played it solidly for about 3 hours that first night. We still play it every time he comes round and now two more of our kids join in, one of whom is an 18yo office girl - hehehe.
This is the most fun I've had on the Wii to date and we have around 20 Wii titles and a Wii Fit.
Yes, it is repetitive, but that's because it's an arcade game - each time you succeed on one of the three missions it levels up, becoming harder next time or unlocking different routes through the mission. I got the game for £15 in a sale, at that price it's a steal!