The Hitchhiker's Guide To The Galaxy, page 678,325, entry 2,460,014:

"Magrathea was a planet used for making other planets. Unfortunately, the employees were often very overworked. To boost morale, the boss decided to get all of the workers a lifetime supply of the universally-renowned Pan Galactic Gargle Blasters. When the planet was left abandoned, the crew accidentally left their drinks. So, while Zaphod and Trillian are exploring the planet, Ford sends Arthur Dent down into the planet to retrieve the delicious Pan Galactic Gargle Blasters."

Collect all 322 bottles and make it back to the ship before the killer mice catch you and take your brain.

Important note from the guide about mice:

"It is common knowledge that the creatures known as mice are pandimensional beings. However, while in their mice form, they must move around through small space crafts. These crafts accelerate very quickly, but turn very slowly. This is not a problem for the mice, though, because they can find bends in solid walls and move through them to get closer to targets. Approach cautiously."

W, A, S, D - Move

Space - Jump

Enter - Menu Navigation

Don't panic and good luck.