From IGN.com
I can't deny it: when Splatoon was unveiled at E3 last year, I found it hard to match the enthusiasm shown by much of Nintendo's faithful. Without getting my hands on it, the concept sounded novel...perhaps a little too novel. But now that I've played it, and seen how immediately fun, and deceptively smart Platoon is, I can understand why people were so excited, and why there was a 2+ hour wait time to play it on the show floor.
The first thing that sets Splatoon immediately apart from other multiplayer arena shooters, is that kills and deaths don't really matter - at least not in the usual, immediate sense. It doesn't matter ow good your K/D is, or how long of a kill streak you're on if you aren't covering every surface in sight with your team's paint color. This one simple concept fundamentally changes your approach dramatically. You aren't looking for enemies to kill, you're scanning the mini-map to find areas that need painting, and wherever blue paint meets orange paint, you can almost always expect a firefight to happen. This is one of the ways that Splatoon keeps you moving, and in the action. There's no wandering around in search of an engagement; there's always someplace that needs a new coat of paint.
Following through with the idea of keeping players constantly engaged, respawn times are short, and getting back to where you're needed is as simple as looking at the gamepad, spotting an ally, and tapping them. You'll promptly (and amusingly) transform into a squid, and catapult through the air right to your teammate's position, ready to go all Jackson Pollock on everyone and everything around you. In a game all about winning fights, this might seem overpowering, but in Splatoon, the trade-off for grouping up is leaving more of your turf susceptible to being painted-over. That mobility cuts both ways.
Even in combat though, mobility is a huge factor. Any painted surface - walls included - can be traversed rapidly by, uhhhhh, "squidding" through them. Holding the left trigger also transforms you into a squid, quickly refilling your ink (read:ammo) reserves and letting you make escapes, or advances that you just couldn't in other games. You might paint up a wall to give yourself a quick way up to the next level above, or move forward along the wall and pop out behind an advancing opponent. Trying to squid through enemy paint will slow and damage you though, so smart players will cut off your advance with some paint of their own. I can only imagine how nutty this will get when people start getting good at all of it.
For this and more go to IGN.com