Finally a light gun shooter with a little thing called depth.
There are 12 main levels, each going for 10-15 mins each, 1 or 2 can take even 15-20 mins each. Plus 12 side missions which take about 5-10 mins each, although they do reuse the same levels of the main game, with the exception of a few new rooms which you will see. In some of these main missions they also have multiple paths, meaning there is a new reason to replay the level, other than trying to get an S ranking, but these paths are only usually about a min long before they come to together again. Speaking of S rankings you are also graded at the end of a stage in terms of how fast you finished, Emmys killed, critical hits (1 hit kills), objects destroyed and files found. Files can be found during the game by shooting objects, these files contain side mission and facts about the each RE episode.
The game also features (I think) 24 weapons which can all be updated, although not as much as in RE:4. The Graphics, although stated by many reviews say the game looks 1 step behind RE:4, but I think it's actually looks 1 step above RE:4, the textures are cleaner and the character animation is more fluent and the overall game looks great, even if it looks like an over clocked GC game.
The controls are great, shooting down zombies is really easy, getting critical hits isn't thoug as they are a bit random, but with some practice you while be blowing of zombies heads like their is no tomorrow.
The game also has over a dozen boss battles (including the side mission ones) and while they are as simple as shot the enemy in the head or its weak spot or in some cases just shot the boss anywhere, they are still very fun and enjoyable and for fans it's nice to face off against old foes in a new way sometimes.
The overall game is very fun and if you are a RE fan, Light gun fan or both you are going to love this game because of its great controls, great graphics, weapon verity, huge amount of content and the good old standby know as co-op play which is amazing fun with a friend, like with all good rails shooters. My only complaint with the game is that sometimes the game is a bit to slow, what I mean by this is that it will sometimes take like 10 secs to go around a corner and while it's ok it is kind of a drag a is as much as I like Light Gun games it kinda sucks that I can only really play a game like this for about 1 to 1.5 hours in one sitting before it gets a bit old. So imo it's best to be play in short bursts, like say about 1 hour at a time, but hey I have been playing about an hour a day of it for 3 weeks and it's still a blast. But apart from that get this game, NOW!