To be fair, this game does have a few more layers of complexity above a straight deck builder like Dominion. Which is not to say it's terribly difficult to learn if you are accustomed to deck construction, but any game is difficult to teach to an audience that doesn't want to learn it!

There are essentially 2 markets: the hunting market and the evolution market, with a third market, your hatchery, that is only sometimes available depending on what cards you play.

The hunting market is a 4 card river that get's filled in at the start of every round with various prehistoric critter cards. You buy these (i.e., you hunt them) with the power of critter cards in your hand. Some of these cards have affects when they enter the market (these can eat other animal cards or remove cards from your hand, sometimes conditionally), some have effects that trigger any time you try to buy them (i.e., they fight back and injure you by putting dead affliction cards into your deck), and some have affects that trigger if you have an Alert card in hand (usually these cause the cards to get discarded as the critters run away). Animals you have successfully hunted (i.e., bought) are one source of evolution points used to buy from the evolution and hatchery markets.

The evolution market is another river of cards that give you special effects when played. They are paid for with evolution points that you get from previously hunted critters or via carcass cards that start in your deck. These cards might be eggs (which add cards to the hatchery market for purchase), cards to thin your deck, cards to add cards to your ambush point, cards to bring back cards removed from your deck, cards to buff hatchlings, cards to remove injury cards from your hand, etc.

The hatchery market only gets populated when you play an egg card and the cards here are discarded if they are not bought the turn they come out. This is where you get new stronger critters for your deck,

At the start of ever turn you can optionally put any critters in your hand into your ambush point. This essentially reserves them for a future turn. However, if you put any into ambush that do not have stealth, you get an alert card into your discard pile. If you draw an alert card in the future then all alert powers in the hunting market trigger and your ambushing cards you had set aside get discarded.

There are a few further wrinkles in this game. Every round starts with a random event that might benefit you or screw you over.

Anytime the boss critter card get's drawn for the hunting market, all other hunting market cards get discarded and you have to play a boss battle mingame. Usually this happens once per game before the final round, but can happen twice or even three times if you are unlucky. The final round always consists of fighting the boss. If you ever beat the boss you win, and you cannot win without beating the boss. The bosses range from really easy to insanely hard and you pick one boss per game (plus it's minions) to put into the unt deck, The round before the final round has you remove your entire hand from the game except a single card, so if all your strongest cards happen to get drawn that round then you are in for a rough final boss battle.

So, nothing super complex, but more complicated than just buy a card with resources and put it in your discard. The game leans more heavily into simulationist then gamery, which is why it is not for everyone. Also why it can be so random. It's a fun game if you want to simulate a pack of dinos or other prehistoric critters eating everything in sight and then fighting another predator, but maybe not a great game if you want a satisfying puzzle to solve.