The critics are being too harsh on this game, even if it has some small flaws, it is one of the best co op games on xbox
First i'll list some things I have found frustrating with the game: Player 2 not getting achivements/rewarded on split screen even if they are a signed in xbox live gold member, The difficulty increasing on co-op compared to single player because you have the same amount of "lives" and the way that the game does not reward players equally or fairly for their achievements. The poor menu system to get into games did confuse me at first as well.
However, with all this said and done - the game itself is a real blast! I love the amount of flexibility in this game: the fantastic vehicles and weapons which feel very solid to fire with, the way that most weapons are fairly balanced and there being multiple fun favorite weapons rather than one, the way you can choose how you wish to fight a boss moreso than most games. the fairly large amount of unlockable customisation... The list goes on for flexibility
The graphics are beautiful, the gameplay is smooth too, even in the largest fights there is not even a whisper of dropped FPS, and this is a surprise since the bosses are jaw-droppingly huge.
The story could have been more explained yes, but the story is there, and I am interested in it. half way through the game, there are many unanswered questions i can't wait to discover.
Another big plus to this game is the difficulty - Hard mode is actually hard! My friend and I are veteran gamers - we usually get through a shoot em up game on hardest difficulty in two nights max.. we have been hitting our heads against this for 6 days now and we aren't even half way through! I really enjoy the challenge for a change, it's ideal for me and my friend.
Contrary to the review, I also consider the AI (at least the enemy) to be quite intelligent - the way they will flank, and the way they know to keep moving to stay alive makes them tough indeed on hard mode.
I hope that all these bad reviews do not deter the developers from making another lost planet - this game is fantastic, and with a few tweaks to the death system in co op, and a better menu system, i'm certain the sequal would prove to be much much more popular - This game has it all!