Also a new Splattershot and Splat Charger, at least skins; two new maps that I noticed; new music; a new Turf War mode (100x Battle)... but no date.
Was that hammer a main or a special? It's huge.
Edit: The SplatoonUS Tumblr has already added details: No new main weapons, just kits, starting with the Kensa Splattershot, Splat Charger, Splatterscope, Roller, and Splat Dualies, at least some of which release tonight.