When you start the game, click the green flag TWICE. For the best gameplay, when it asks you whether you want to skip the tutorial or not, click no. There is sound. The microphone button at the bottom will mute(mostly). When buying upgrades, click on the photo, not the words.
This is my second project on Scratch. Go to this link to see my first. https://scratch.mit.edu/projects/951716737 Also, thank you to my dog, Penny, who is the photo for "Puppy" upgrade.