This is about a feat primarily destined to animals. Clever Critter makes a creature of animal intelligence significantly smarter, increasing its Intelligence by 2, giving it understanding of simple sentences in one spoken language (if it has a trainer), and some basic understanding of other humanoid stuff.
Then there is the Note that really bugs me :
Note: This feat effectively grants the animal an additional skill point when it gains HD and allows it to learn any feat it can physically perform.
The part about removing the choice limitation for feats is mentioned in the Animal Companions rules as well, and that's exactly what I was expecting from an Intelligence increase, but the one about the extra skill point per HD really needs clarification :
Does this mean that an animal with this feat will automatically gain 2 skill points per HD, or does it just remind the reader that the Intelligence bonus is taken into account in the calculation of skill points ?