You will understand the controls when you start, there are on-screen tutorials. When an item or event appears, it says to press space, and lists what happens if you do. You can leave the room and the item/event will disappear, and nothing will happen.
As always, I am open to suggestions for the game! The "Golden Bugs" listed at the bottom of the screen are rare enemies found by players. There is a 1 in 1000 chance(0.1%) that any enemy on screen is a golden worm. Consider yourself lucky if you find one. As of this version, I have somehow found 3 golden bugs while testing. Click "See data" under "Cloud variables" on this page to see the history of players finding golden bugs.