After watching lots of videos for this...
Lets see. 2 player co-op. An inventory. If one player dies, you can revive him with some sort of pill.
Raptors are playable.
Items can be equipped. They can have fairly good stat boosts and animals can have multiple accessories on at once. Even raptor.
Stat boost case:The one I noticed is the pomeranian had a base 32 damage. With just a spike hat hit jumped 20 points to 52. It had three more equip slots.
You have to reach a certain rank to be able to attract certain mates.
Once you mate (on a generic "nest" of straw) you control the next generation which comes with a stat boost and starts out tiny. The adults... uh... stand there? You can instantly grow to adult hood by sleeping at the nest.
I'm not sure if babies born is random or fixed for the same species. Player takes control of one leader animal and the rest follow your movement actions perfectly until combat starts from what I can tell. Only the one player animal is equipped? Maybe boss animals like boxing kangaroo.
Flag markers are... some sort of territory marker? Animals have different animations for marking them-red is not owned by player, blue is.
Rank goes up with kills. It "may" also go up with territory. You have a map which shows potential mates as hearts.
Stats go up at several times. I noticed both after a kill, with accessories, and after mating. May also go up with inventory items.
You have to finish the tutorial to play the game. Required.
That's all I've gathered so far. ... Erm, actually, that's all I remember. It's been weeks since I saw all those videos.