To begin simply click "Play". You do not need to register, though you cannot get onto the high score list without logging in. Registration is free by providing a nickname, your birthday, and an email address.
Everything in this game is controlled with the mouse. When the game begins, one of the hens will lay an egg on the see-saw. Depending on the size of the egg—small, medium, or large—you will want to pick up an appropriately sized animal as counter-weight. Click and drag the hare, bear, or hen to position it above the see-saw. Drop the animal to catapult the egg, up and over, to the hare waiting on the other side. When the egg is launched, move the mouse to position the hare and catch the egg in the basket. Play continues until you miss 5 eggs.
You can use the owl as a guide to see if your chosen animal is of the correct weight and height to get the egg over to the basket. However, the owl does not react very quickly, and relying on the owl will cost you points since the score an egg is worth begins to count down as soon as it is laid. Still, the owl provides valuable information when just beginning to learn how to play.
Graphically, the game is polished and über-cute with lovable animal characters and humorous animations. Eggs sparkle with particles and sound effects in-flight, and create a very satisfying sound when caught. Although the soundtrack is whimsical and catchy, it is a bit repetitive. Fortunately the developer, Extrajetzt, included a sound button to turn it off, just click the musical note.
Eier Wuppen is excellent Easter fun for gamers of all ages. Click.
Update: As Laura pointed out, the German site that was hosting the game has removed it from their server. If the game surfaces again someday, I will link to the new site and update this entry accordingly. In the meantime, I have removed the game from the recommended section.