(You might argue that in honor of Earth Day a company might vow not to release something that could be regarded as disposable entertainment, but since 2006 BOG has had a policy of planting two trees for every tree used in the production of its wooden games, and in addition it works with PUR Projet in France to plant trees to offset the carbon emissions the company creates while driving across the U.S. to visit retail stores, and that's far more environmental-boosting work than I've done in response to my activities, so who am I to talk?)
In Planet, each player has a dodecahedron with magnetic faces that serves as a planetary core, and in each of the twelve rounds of the game, you add a magnetic landscape tile to your world to create habitat regions. Five types of landscape are included in the game, and starting in the third round animal species cards are awarded to the player who meets the landscape condition stated on that card:
• Largest region of landscape type X that touches landscape type Y,
• Largest region of landscape type X that doesn't touch landscape type Y, or
• Most regions of landscape type X.
In case of a tie, the animal card moves to the next round, giving everyone a second chance to call dibs on the walruses.
Each player also has a secret landscape card that gives you 0-10 points at game's end depending on how many triangles of that landscape type end up on your planet, and that landscape type determines how many points you score for each animal card that you collect. If the animal is from the same landscape as your secret card, you score only 1 point for it; otherwise, you score 2 points.
This scoring rule keeps you from mindlessly focusing on collecting one type of landscape at the expense of all others. You want to both maximize your endgame scoring and scoop up as many animal cards as possible, but you can't do it all, which is a basic feature of good games. The rules pull you in different directions, creating tension over what to do and driving interaction with others since you're competing for the same things and one or more players will lose out to the benefit of someone else.
Planet isn't complicated, but your playing time will differ depending on how much you want to grab other players' worlds and spin them around to determine who has how much of this and that landscape ahead of each epoch of animal distribution. You could calculate every possibility for who can score what depending on which landscape tiles were revealed at the start of a round, but I predict you'd catch a dodecahedron in the face before too much calculation ensued — which means you'll have to wing it to some degree, slapping on the tiles, then seeing how you measure up, each creator in a universe apart from others, ideally satisfied with what you have since it's the only world you've got...