Secret
Chase down the green fireflies/faeries on the loading screen, then click on them to make them disappear. Next, proceed to your "Stats" screen to see how many you captured under "Faeries Captured."
Easter Egg: Alternate Loading Screen
This Easter Egg requires some skillful mouse-over work, so don't mouse over things at random. Instead, mouse over the buttons in this exact order:
Duel, Duel, Challenge, Replay, Replay, Challenge, Duel, Quickplay, Adventure, Adventure, Quickplay, Duel, Duel, Quickplay, Quickplay
This should display an alternate loading screen. If it doesn't work, you will have to reboot the game.
Unlimited Balls
You'll need Cheat Engine 5.4 for this to work. First click the processes button cheat engine, then look for peggle.exe or popcapgame.exe. Click ̶0;OK.̶1;
Start a game in Peggle Nights. Type the amount of balls you currently have into the value box, then click ̶0;First Scan.̶1;
Go back to Peggle Nights and shoot a ball. Go back to Cheat Engine. Type the amount of balls you have now in the same box as before. Click ̶0;Next Scan.̶1; On the left you will see one entry under the ̶0;Address and Value̶1; box. Double click this entry.
Look at the bottom of Cheat Engine, where you should see the entry now in the box. Double click the value and change it to any amount from 999 to 99,999,999. When you go back to Peggle Nights you should have the amount of balls you typed in.