Recently, ratio changed have either gone UP or DOWN. This basically means that before, you may have had to score 1000 points to get 1000 neopoints, which would have a ratio of 1.0. These have now changed, and you'll have to get more or less points for a perfect neopoint reward.
Here are a list of SOME of the games that have gone up (meaning that you get more neopoints now, but still a maximum of 1k):
Meerca Chase II
Usuki Frenzy (average game gets about 450np)
Whack A Kass (gone up drastically, about 850 is 1k)
Snowmuncher (gone up drastically, you know need 2800 for 1k)
Suteks Tomb (700-odd points for 1k, 800 to be sure)
Extreme Potato Counter
Ultimate Bullseye
Magax: 2 (gone up drastically, 160 is the 1k, so you don't even have to finish level 1)
Zurroball
Jelly Blobs Of Doom
Evil Fuzzels From Beyond the stars
Spell or starve.
Some of the ratios that have gone DOWN:
Wingoball
Monster House (as well as many other of the sponsor games such as Limo Chase etc)
Jolly Jugglers (ouch)
Feel free to post all/more of the ratio changes. Hope I could help.