What's the level design like? Have the new Pikmin affected it much? Is there more to explore?
Level design is actually similar to that of the original. Valley of Repose is a new area itself, Awakening Wood looks similar to the Forest Naval (but the whole layout is different), Perplexing Pool is a half and half version of the Distant Spring (some areas are new, some are the same, some pieces are in the same spot too), Wistful Wild, the final area, is a mix of the Impact Crater and the Final area where you fought Emperor Bulbax in Pikmin 1.
The 2 new Pikmin are Purple and White, and to an extent, Yellow. Purple's are 10x stronger than regulars, which would be yellows, whites, and blues. They also have the ability to stun many enemies when thrown, making them great for taking out Bulborbs and other monsters. The purples's can also carry 10x they're own weight, basically, they count as ten pikmin when they carry an item. The downside? They're slower than all of the other Pikmin, even with flowers, meaning you have to wait for them often. They also carry items very slowly.
Whites have the special ability of surviving the new hazard of poision. They are also the fastest of the Pikmin, and can carry items the fastest. Also, when white pikmin are eaten, they do some pretty heavy damage to the opponent.
Yellow can no longer carry bomb rocks, as the bomb rocks now fall under Hazards: Explosion. They can however go up against electricity. They are still thrown the highest.
Red is about 1.5x to 2x stronger than the regulars, making them the best fighters for swarming enemys (purple's are too slow).
Blue is still the same, and when idle in water, they act as life guards for drowning pikmin a.k.a throw them towards land.
Also, the dungeons were a great addition to the game. The day limit stops when you're underground, but you CANNOT grow more Pikmin unless you find a certain candypop bud, 1 dungeon go's to about level 14 or 16.
One last thing. The challenge mode is more like "Dungeon Time Attack". Its one to two players working Co-Op, so its good fun. So is battle mode. Yes, nothing beats rocks falling on your opponents Pikmin.