As written on the webpage,
Welcome to the world of Ick! where you're only as good as you are gross. In this fast-paced game, players collect a colorful assortment of monster cards and place their monster's favorite gross stuff (from toxic slime to gooey eyeballs and severed limbs) into a monster's dream house—a mildew-infested shack. King Stink cards can steal a player's loot of monsters and gross stuff, allowing for plenty of quick, silly play. When the cards run out, tally up the points—whoever collects the most gross stuff wins! Official Site

Basically it's as above, players get hand full of cards, set down a house card (if they have one) put crap in it (making as many objects as they can) and capping off with the moster that belongs with the last object placed. That is player A has 6 cards on his turn; A house, a bandaid, fishbones, rotton veggies, maggots, and the monster known as Slimon. He lays down the house card, followed by all of the item cards he has except the maggots. He can either end his turn or place the maggot card and them slimon monster card to end that pile of cards from play to others except for the one monster that takes over any house. Basically the objects add up 5 points each and the first person to 100 wins the game.