Play Galaga Ghosts (https://scratch.mit.edu/projects/322585089/). If you win, the ghost will say a code. (That's the Adventure Code the register's talking about.) Type it in here, and you will get 50 points. If you win enough times, you can buy an upgrade. Koo Koo Kannon costs 100 points, the shield, 200 points, and the bomb costs 400 points. To buy an upgrade, click on it once. It will say a code. Press U in Galaga Ghosts (the game), type in the code, and hit return. Now you have upgraded!
If you want to know about other upgrades, here's a link: https://scratch.mit.edu/projects/380336112/
