The beginning bit alone is worth watching the movie. Of course the movie has to settle a bit after that much mayhem, but does pick up the pace towards the end again. The comedy action mixture is really fitting and the actors are doing a great job. It's obvious they have fun with the script and the comedy that ensues.
It may seem all over the place and a bit over the top (alright sometimes a lot over the top), but if you don't mind that, you will be entertained as much as I did. South Korea has some really good filmmakers and some great talent in general and here are some on display if you are open minded and love originality, than you should give this a try