There are quite a few new mechanics in both the battle system and the game's overworld, and fans with fond memories of the other Mario RPGs will likely relish the chance to level up the Italian plumber yet again.
Once you do into combat, Sticker Star plays out like a turn-based battle, albeit an extremely simple one. On Mario's turn, he has the ability to use one of the consumable stickers you collect throughout the rest of the game on the 3DS' bottom screen, and then you can see him put that effect into action on top. A boot sticker, for example, has him jumping on heads, while a Fire Flower sticker will throw a fireball when selected.
Each sticker also has a quality rating, from the plain matte stickers that will pile up in your inventory to more rare foil and golden stickers, with stronger effects and more value. The timing system from previous Mario RPGs is back too: you can hit A at exactly the right time while attacking to ring up extra damage, or at exactly the right time when being attacked to block incoming damage. It's simple to pull off, and surprisingly effective. It seems a bit too easy to be so powerful, at least at the beginning of the game.
Outside of battle, Mario's stickers work in an adventure game style. He can pull them off the wall and collect them as currency or in combat, or he can turn in-game objects into stickers (or vice versa) to solve puzzles that open up new areas to explore. One example shown during the PAX demo was of a windmill, which has its door blocked by one of the sails. Mario is able to move through by finding a giant electric fan, converting it into a sticker and then sticking it in the right place.
Paper Mario: Sticker Star is getting stuck to shelves on November 11. Just do your best to remember that jumping on that Goomba means you're getting a battle, not points.