Want cheats? Type 09241993 in Classic Mode or Party Mode's "You Can Think Pad", and press Enter on your keyboard or click OK. The game should send you back to the menu. Start a game, pause it, and click the question mark on the top right. It should bring you to the cheats menu.

Have fun!

Also, it seems to disable when you close the game, meaning you have to do it EVERY SINGLE TIME you restart BBCR. There'll probably be some mod that keeps it always enabled though soon.

Also, as this guy said, achievements get disabled when you do this. Hopefully only as long as you have this enabled though, I've always been bad at Baldi's Basics though, so I'm not going to get any achievements anyway.

Too lazy to read? Want to make sure you did it right? Watch my YouTube video on how to do it!

update:
Mystman patched it in 1.0.2.
Apparently you have to find all the secrets first, so, yeah. You can either do that or use an older slightly outdated version.