Timecop clearly wasn't filmed to the very highest technical standards - I was struck by the contrast with Alien (a 15-years-older film) which I watched on broadcast HD the same evening. That said, Timecop is high enough quality to make the Blu-ray transfer worth having. I am not sure I would recommend getting the Blu-ray to replace a DVD unless you have money to burn, but definitely worth the extra if you just want a copy to add to your library. As usual with Blu-ray, you can pick out details in printed signs etc., in the scene backgrounds, which is interesting in its own right. The sound track is fine with plenty of punch in the explosions and gunfire. Also, whatever the details of film stock, cameras and so on, the colour palette of the movie is often rewarding.
As for the movie itself, it keeps drawing me back despite its flaws. Its handling of time paradoxes seems vague, almost as if it's a time-travel movie made by people who don't actually find time-travel very interesting. The plot is skeletal. Still, the emotional aspects work despite - or perhaps because of - Van Damme's rather flat portrayal, the narrative drive is not lacking, and the near-future setting has a curious plausibility. Perhaps because of budget limitations, most of the future world is still our old one - actually more likely when you think about it. Some of the B-movie / budget-limited aspects - a time machine that accelerates by spurting rocket flames out the back, for luv's sake - will generate affection or derision, according to your taste. As you will guess, I tend towards affection.
Finally, the James Bond cast-off one-liners ("that had to hurt" after killing a baddy, I mean come on!) and the (deliberately? but surely not) risible demise of the arch-villain, well, take them or leave them, The Terminator this ain't. But nonetheless a film that, I suspect, has enough to draw others back regularly as it does me, so if you haven't seen it or want to re-acquaint, this Blu-ray is definitely the best option. Recommended for those, like me, who feel enough intuitive attachment to this odd, semi-cult movie to want to own a copy in HD rather than waiting for it to turn up in HD on broadcast. I hesitated for some time between 3 and 4 stars, and would have given 3.5 stars if feasible.