The symbols on the reels are 2 things, wool and cats. Different colour wool and different colour cats. Cats can turn double in the base game whenever a wild land in the winning combination or they can land as doubles naturally as well. This is almost like the double stacks slot with symbols appearing double on the reel, which obviously increase the win line significantly. The most lucrative cat, the black one, can therefore give you pay-outs of 100 times your stake if you get 10 on a payline.
There’s also a wild symbol which substitutes for any symbol except the scatter. If a wild is included in a winning combination, the cat is doubled. The wild symbol is stacked in the bonus game feature. Value wise, 10 wilds will give you 100 times your stake as well.
The Bonus Game feature is played when you get 3 or more free spins scatter symbols on reels 1, 3 and 5 – 3, 4, 5 or 6 scatters will reward you with 10, 15, 20 or 25 free spins respectively. The free spin scatter can also appear as a double symbol which makes it easier for you to trigger the feature.
I do not now know why it's called not enough kittens, because there are certainly more than enough kittens, or is it because the wool is mostly landing on the reels? I don’t know, but I know for sure this game is all about the free spins because of wild stacks, so do not expect big wins in the base game at all.