Stranger Things 3: The Game

Story-related and cannot be missed.

Joyce will unlock when you speak with her at Melvald's at the beginning of Return to Hawkins Lab. Joyce has the bolt-cutters, which are used to open all those chained gates you've probably seen around Hawkins. Hopper, meanwhile, can be found in his cabin and he will join your party when you talk to him as Joyce.

During their mission together, Return to Hawkins Lab, the rat statue puzzle solution is: One faces the poster, one faces the wall switch and one faces the bookcase, then use the light switch to turn the lights off. If done correctly, you'll see the door open.