Welcome to the Laboratory, where you will go through an endless gauntlet of increasingly difficult enemies while racing against your slow but inevitable decay... Time is ticking by, so here are some basics to get you started:
Your health drains over time. Killing enemies, clearing rooms, and stepping through the portal will heal you and delay your doom
WASD for movement
Click or hold the left mouse button to shoot
Hold the right mouse button to see the map
P to pause the game
E to collect upgrades (the diamond-shaped objects which some enemies drop).
Find the portal in one of the rooms and step in it to go to the next level! The portal will have three upgrades to choose from, but they each overrule the other options, so be sure to pick wisely.