"Extreme Crisis" is what we typically refer to as a "no-substance" kind of movie. If you want things like character development, cohesive plotline, and drama... go watch "Infernal Affairs." If you want a movie that's about 20% talk and 80% action, then this movie's right up your alley.
The story (thin, but still present) revolves around Kenya Sawada's character, an SDU team leader whose entire squad is wiped out by a terrorist cult in the first 5 minutes of the movie. Stricken with grief, he visits all of their graves on a regular basis. One day, though, a hot-shot cop (played by Julian Cheung) meets up with him - because as it turns out the terrorists that had killed the SDU team are now planning a sarin attack on all of Hong Kong.
Much shooting, exploding, and chasing ensues.
In this movie, the terrorists are extremely cold-blooded. When they take over a TV station, you can be assured that there'll be more dead hostages than living ones by the end. There's even a scene where a child gets shot at point-blank range. Also, don't get too fond of the characters in this movie. Without spoiling anything for you, I can say that not many of them make it to the end.
All of that aside, the movie's strength rests in its action scenes - which are some of the most well-done I've seen in a long time. My favorite would probably have to be a tense shootout/fistfight inside of a restroom. There's also other eye-candy as well, like a scene in which a row of police cars are simultaneously blown-up, flipping in the air almost like an automobile-ballet.
So, in the end, if you just want an action movie for action's sake, Extreme Crisis is a good way to go. If you want something that'll leave a lasting impression on you, look elsewhere.