To be honest I think coyright laws with films are a little loose. I remember someone telling me you can take some of the concept of the film, as long as you don't copy scene for scene.
With novels they are quite strict but with films its tends to be a diffrent ball game. I watched Disturbia a couple of years ago and that was a clear copy of Rear Window to me.
The 2008 copy was a copy of the 2005 copy (though it had the same director and everything - they were just in different languages).
I watched the 2005 version and found it pretty annoying (because the direction was stupid and I hated all the song and dance crap, the melodrama etc). Though to be fair I haven't watched Memento yet, but I have no doubt that Memento is clearly the superior version.
I'm surprised that Nolan hasn't sued yet too. I think the 2005 and 2008 films (combined) grossed more than Memento.
The 2008 film alone grossed over $38.3 million (apparently the 2005 film grossed $5 million in Tamil alone - it was later dubbed into Telugu too) while Memento grossed $39.7
I really hope the Indian filmmakers get sued so that they can come up with original movies for a change.
I'm a BIG Nolan fan from india and have seen both the rip off versions (the 2005 one and the 2008 one too).
Both are crap....melodrama ...songs (unnecessary) ...and dumbed down revenge drama (no drama in the films per se)
The same filmaker has made both the films ..and he went around denying the fact that he had basically lifted up scenes/story/characters etc from memento and copy-pasted them.
It's a pity. Among the nolan fans here, the joke was that Nolan should go around with a tattoo on his chest saying "Murgadoss raped and murdered my film"
(P.S - Murgadoss being the director of the copies)