A decent attempt
All you need to know is that the character you play (called Scott) is going out with a 'serious eurasian hottie' who's father happens to be a mobster. She gets kidnapped by a rival gang, and you're forced to grab a gun and rescue her. Amongst all this there's the cliche 'man must fight with honour' ethic you see in pretty much any Japanese Samurai movie.
The game controls pretty well for the most part, though it may feel very unnatrual for the first 20 minutes or so but once you get used to the odd turning and sensitivity issues you shouldn't have much of a problem. Ubisoft did fall into the trap of using motion controls when they're not really neccesary - you will move the Wiimote towards the screen to zoom in on enemies with the sniper rifle (which is kind of broken) and use the nunchuck to throw grenades (which actually feels awesome when you pull it off). Again, inconsistancy is Red Steel.
What is more annoying is that they leave out the motion controls you probably imagined when you first heard about the game - 1:1 sword fighting. Instead, you have this cop-out system of slashing up, down, left, right, diagonally etc. It doesn't really feed good and the moves you learn later on in the game are overly complicated and hardly ever register. The sword fights are awkwardly put into the game usually after you've cleared a room full of enemies. On one hand they're a nice break from all the shooting but on the other you're always thinking "why can't I just shoot his face off with a shotgun?" Again, inconsistancy.
However, nothing is more inconsistant than the visuals. At the start of the game, they look pretty bad with mediocre character visuals whose lips don't even move when they speak and bland wall textures. But as you get further into the game you'll see nice reflections, insanely bright explosions and lush environments... And then you'll walk through a corridor with a horrible, muddy N64 quality texture smeared across it. It is highly evident that this was a rushed game. It really is a shame because Red Steel has a lot of potential...
What the game does have is atmosphere and this weird sense of charm. I grew up in the 90's and loved playing arcade games with bad voice acting and enemies that all looked the same. Red Steel has both. You'll find enemies saying stuff that doesn't quite make sense in context (like a gangster yelling KILLER at you or saying "I lost him" when you're standing right next to him) and this just makes me feel nostalgic.
Ultimately, red steel tried to do too much in too little time and it won't age well. There are far more better FPS'ses on Wii with tighter motion controls and prettier visuals. However, if you like games that are so bad they're good then give Red Steel a rent. It is top quality cheesy game goodness.