Teamwork is essentially the biggest the key word when it come to this games competitive scene, since some smash players are more accustomed to playing 2v2 matches it is definitely gonna be interesting to make that type of transition. I myself have played the demo of splatoon at pax east and trust me when I say this, don't wander off alone, if you do then be very careful because not only is it easy for you to be spotted and taken out but you can cost your team the match possibly. Another side note is that Offense is not that crucial during certain parts of the matches, points are based on how much ink is covering the ground, emphasis on "ground" walls and everything else does not count. however in order to obtain powerful weapons during matches you will need to get some kills. Teamwork is so crucial, one of the guys i was with at the splatoon booth always had my back and vise versa, we ended up having the highest amount of kills and never lost a match (we only played 3 matches so that may be exaggerated :P )