It's a Thai Sci-Fi movie! It's your basic horror scenario - evil clone escapes from lab and starts stalking you and your loved ones. If it hasn't happened to you, I'm sure it's happened to someone you know. It's funny, because he can do everything a normal stalker can - but he can also make everybody you know think he's you!
OK, the plot is pretty thin - quite why the evil clone wants to take over your life and then kill everyone you know is really never explained, though there's some vague suggestion that maybe a clone doesn't have a soul or something. Or maybe it's because he's only 3 years old, since the clone ages at 10 x normal speed. The 3 year old kid in a 30 year old body angle isn't really explored though, and is blatantly ignored when issues like being able to drive a car are concerned. After all, it's just an excuse to make the same actor play a cold hearted psycho and a... err, well, the original wasn't exactly mister sweetness either. But who can't relate to his plight when he knows his evil clone is in the house with his mother, and the police all think it's him that's been killing scientists and the like?
If I were inclined to be nasty about the movie, I would say that it has a dopy pseudo-science plot that is developed in a particularly haphazard way like it knows where it wants to go but doesn't realise that it has to navigate some kind of narrative structure to get there. I'd probably criticise the acting too. If, on the other hand, I were inclined to be nice about it, I would mention that it's very well filmed. Great sets & lighting create a cool sci-fi feel, and there's some pretty nice camera activity. And it definitely takes some effort to shoot scenes where one actor is playing 2 parts, and trying to kill himself no less, so marks for effort there.
Overall... I would like to be nice about it, but I can't really avoid the conclusion that it's not really a very good movie :(