The music of a game is also very important. It ensures, among other things, the right atmosphere, even during the making of your game.
On Unreal Engine's Marketplace I came across the mega music collection from MuzStation. From where you can buy very cool music for any kind of game!
Just take a look at https://www.unrealengine.com/marketplace/en-US/product/mega-game-music-collection
Making sounds is a real challenge...
When you are busy with those parts of your game, your hearing starts to change. In almost everything you hear in your environment, you wonder,
"Can I use that sound in my game?"
Squeaky doors in an old house are come in handy, especially if you live in it. I just had to record the sound.
But I also invented and made many sounds myself. For example the sound of skating PIP;
A colander with multiple functions...
Then I edited my recorded colander-sounds with Audacity,
to match the "skating PIP" game scene;
Audacity is a free, open source, cross platform audio software. Look at https://buildingbeats.org/toolbox also for more music and sound tools.
For instance the logo of PaperMill Games with the intro tune. That, I made with BeepBox, with which you can produce your own music.
I wanted the tune to be like barrel organ music (press for play):
And last but not least,
I would like to thank Guapo, this sweet dog is Star's "voice" actor