There have been loads of these knock-off flicks, including cheeky cash-ins on Iron Man, Alien Vs Predator, War of the Worlds and even High School Musical. All of them are marketed to look very much like the films they are pastiching, and pretty much all of them are terrible.
Transmorphers, let's not beat about the bush here, is crap. That said, it's entertaining crap. With its dire cast and its hilariously cheap CGI, it should be an absolute car crash, but it's actually kinda fun in its own way. Rather than ripping off the Transformers movies, it rips off a bunch of other big Sci-Fi blockbusters including The Matrix, Blade Runner, Aliens and The Terminator, amongst others. This makes it fun to pick out where different bits have been lifted from, but it also means that it makes for some entertaining background noise full of explosions and robots.
The film is shot in a style that is quite blatantly intended to look like the Battlestar Galactica remake, and as such looks much nicer than many other Asylum projects (and features some impressive sets), but it's still tosh. Robots have taken over the earth, and after 400 years, man is finally fighting back. A rag-tag group of resistance fighters bicker underground for much of the flick, but once it gets a bit Aliens and guns start a-blazing, you're treated to fun involving z-grade 'actors' blasting away at marvellously cheap video-game style CG robots.
The script, tacky as it is, is still above the skills of the cast, who all look above fifteen years too young for their roles, and whom can barely manage the lines they are given. Such is the level of cheese that I'm reminded of the short lived Captain Power TV series, but at least even that had some innovation to it. Transmorphers is a big, fat rip-off, but it's also one of the most audacious cheapo movies made in recent history. It even spawned a prequel, Transmorphers: Fall of Man, and even though these films are terrible, they still walk all over Transformers: Revenge of the Fallen.