This will be a long post analyzing the content in the trailer. Gaffers and some youtubers (and the official twitter! nice) have covered a lot of it probably but I'll go for it anyway. Maybe I spot something no one has.
Multiplayer
In the front and pic 2 we have a clear shot of the sniper rifle. Seems functionally the same from the previous trailer. Long range, precise with laser pointer, and probably low paint output. On the right is the paint roller. In pic 3 the squid boy shows off a new move: a jumping paint roller smash. This is probably a good way to avoid being shot in close quarters if your opponent sees you, jumping into the air away from their previous aim then coming down with the killing blow. It might also be used to paint walls so the roller isn't confined to the ground level. On the left is the familiar super soaker machine gun, looks unchanged.
The left inkling is holding a new weapon. I think the closest relevant item it resembles is a motorized spray paint gun. I first thought it looked like a nail gun but that wouldn't make sense. Maybe a close range quick-firing SMG-alike. On the right is another new weapon which looks to be a combination of a fishing pole and a spray bottle. In pic 2 you can see it has a laser guide like the sniper rifle which confuses me. I'm thinking it might be a semi-fire medium-long range weapon 'cause I don't see the need for two sniper rifles. Maybe it's something surprising though, like shooting a fishing hook and line.
On the left is a big ol' paint brush. Very stylish too, not like the obvious tear drop shaped brush. It's definitely inspired by the crazy big brushes they have in Japan (are they ceremonial? used to paint big signs back in the day?). It would be cool if this was like an ink sword, cutting your unique strokes on the battlefield. It could also be motorized, spinning into a circular blade or just whipping ink everywhere. edit: Looking at it again the metallic cone-shape connect to the brush looks like a paint tube, cool. So it's probably not motorized.
The grenade has undergone a a change, it's no longer a mechanical tetrahedron frame with flashing lights as a timer. Now it's a spherical ink blob that seemingly explodes on impact. Upon closer inspection of my screencap I noticed a little knot on the top, it's a freaking water balloon now. Awesome.
This inkling was able to generate a spherical forcefield that blocks all inkcoming shots. It's probably one of the special weapons you can acquire after building up enough points.
This new Boardwalk stage reminds me of a summer camp. It looks very open with the lack of walls like the Oil Rig. Seeing as water is in the out-of-bounds areas I take it inklings will dissolve if they fall in.
I forget who suggested it in the E3 thread, but look! The Skate Park is actually in the game! It definitely fits the style of Splatoon. The map appears to be very narrow and straight across. Also it seems they showed it at E3 but no one really picked up on it. In pic 2 that's the same wavy ramps and outdoor shopping mall they showed, but now it's more obvious it's a skate park. So to StreetsAhead, it looks like "Skate Park" and "Side-streets" are the same level.
So the known multiplayer maps are:
City
Oil Rig
Camp Boardwalk
Skate Park
This took a while to put together. I'll do singleplayer later. But one more thing:
The cat ref. What is up with him? Even in this comic panel I can't tell what he's doing.
So mysterious.
