A very quick rundown of the way a Pikmin game is played, for those who never experienced the first. You harvest Pikmin by pulling them from the ground. These little guys have a variety of powers based upon their color and appearance, and will follow you around and do your bidding. You can tell them to carry things, attack things, and generally interact with the environment. If you kill an enemy or find a numbered pellet, you can have your Pikmin carry the offending object back to an onion, one of three color-specific home bases for your Pikmin. Through this method, the onions will produce more Pikmin for you to pick, so you can increase your numbers and tackle tougher puzzles and enemies.
The object of the first Pikmin game was to find the scattered pieces of your spaceship and escape the planet within 30 days - the amount of time you had left until your life support system failed. This time limit, a source of much frustration for many players of the first game, has been removed for Pikmin 2. The day/night cycle is still in effect, but you have as many days as you like to accomplish your goal. This time around, youre sent back to the planet in a desperate attempt to gather funds for your company - which happened to go bankrupt while you were stranded during the first game. Captain Olimar and his new as of yet unnamed companion are charged with finding various doodads on the planet, like marbles and crushed cans, which they can sell for hard cash. Your goal is to find 10,000 Poko worth of doodads to save your company.
The demo landscape was similar to the landscape of the Forest of Hope level in the original Pikmin game - generally grassy, patches of water and dirt, and some narrow corridors. Many of the landscape features from the first game have returned, like stick walls and pellet-holding flowers, but there have been a number of notable additions.
A new type of wall was present in the demo - a wire electric fence. Its built from several wires that protrude upwards from the ground to the typical height of a stick wall, and then bend over 180 degrees and re-enter the ground. As far as I can tell, these fences cannot be destroyed - at least, not with the methods at your disposal in the demo. Throwing a Pikmin at the fence yields a quick sizzle and a speck of ash, so steering clear of them seems to be the best course of action.
One section of the map was infested with a cobweb-esque fungus, centralized around three main humps. Attacking the humps with Pikmin caused them to shrink in size, and eventually disappear entirely - along with a significant chunk of the fungus that surrounded them. As each hump was destroyed, a new type of flower sprung up from the fresh ground. These flowers are the backbone of a new system in Pikmin 2, the acquisition of berries and the development of sprays.
Each flower has five small circular berries growing on it, and diligent Pikmin thrown to the top of the flower can knock them to the ground. After carrying ten of these berries back to your spaceship, theyre automatically processed into a red and spicy extract. This extract is mapped to your d-pad, and can then be used in the field. When you use it, a red cloud of gas comes out in a radius around your spaceman of choice, affecting all Pikmin within its reach. These Pikmin are invigorated by the spiciness of the extract, and their attack power increases exponentially. Their leaf or flower tops turn into glowing balls of fury while the extract is in effect, and return to their former state after a set period of time.
You start the demo with 10 sprays of the red extract, and 10 sprays of another purple extract. I assume this can be refined from purple berries, but there were none present in the demo. After defeating a certain enemy, though, a puddle of purple extract with the power of 10 purple berries was plopped onto the ground. So apparently these supportive sprays can be collected in manners other than harvesting berries. Anyways, the purple spray doesnt affect the Pikmin around you, but is instead an offensive spray that your spaceman shoots out in front of him. If it comes in contact with an enemy, that enemy will be instantly turned into stone. The enemy will eventually return to normal, but if you attack it with Pikmin while its frozen, it will go down in record time. The only downside to this is that you dont get a body to carry back to your onion if you defeat it while its made of stone.
The enemies on the surface included the standard Bulbears from the first game, as well as several new enemy types. There were crustacean creatures with pincers that lived in holes scattered throughout the area. If you attack them with Pikmin in a standard fashion, you cant do any damage and get quickly defeated. You have to lure them out of their holes with your Pikmin from a distance, and then quickly attack their soft hindquarters before they can get back in their holes. There were also small bugs that climb up the berry flowers and eat the berries. These could be easily killed, but if left to their own devices for too long they significantly lowered the number of berries on those flowers.