The NP ratio tells you how many Neopoints you'll earn for every point you score while playing a game.
For example, if the NP ratio is 100 NP for every 150 game points scored, to earn the maximum 1,000 NP reward for playing, you'd have to score 1,500 points during the game.
On the other hand, if a game's NP ratio is 25 NP for every point scored, you'd only have to earn 40 points in the game to get the full 1,000 NP for playing.
Whirlpool:
As any Maraquan could tell you, whirlpools can cause all sorts of damage on the ocean floor. Now, though, those swirling funnels of water have been put to good use! A bunch of Maraquan Petpets have wandered too far from their homes, and they need your help to find their way back. Use the whirlpools to direct those swimming strays back to the comfort and safety of their shell. Keep in mind, however, that whirlpools can be unpredictable – some can be moved while others cannot.