Natural selection is the process where the fittest, the toughest, the most resilient survive. This game basically mimics this... albeit in cartoon form, with some cutesy animals/insects. So, here we are, a world where u eat or u get eaten. You're not a top level predator in this game, something more like middle management. Your objective is to eat the guys below you, but avoid getting eaten by the guys higher up than you in the evolutionary danger scale.
Use your spiders web to swing yourself around the levels, trying to catch your dinner. Of course, watch out for guys who want to eat you as a snack. So swing carefully, swing quickly, and you will survive. Be less than perfect at it, and natural selection will take over and it will be the end of you.
That's it in a frookshell - its a game of skill, action, and speed.