Movie games usually do not do that well... The reason? They never have enough time to do them properly! Think about it--this game is coming out the same time as the movie... which means that they've only known so much about the script, the robot designs, etc., for about a year (the way things are leaked, something tells me they've known more or less what we know when we knew it).
A year might sound like a long time... but when you consider design changes, plot changes (hey, there might be some since that year old script... hopefully), and the difficulty of the engine involved with playable characters that transform, it really isn't enough time to put together a solid videogame, let alone 6 or 7 video games (Xbox, PS2, Gameboy, etc., etc.)!
I'm not trying to excuse them--just stating the plain fact. Video games based on movies will suck 9 times out of 10 unless a lot of information is known about the property ahead of time.