Clock puzzle

[Sky]

What does the clock do at the end of the game area because I've used the uv light on it, and it shows numbers but I have no clue what to do, so i'm just wondering if I'm missing something

[Perseus]

The numbers refer to minutes, each one's door is open until that many minutes have passed in that savefile. After closing, they don't open again.
They're speedrun challenges, you have to reach the clock really quickly to get the rewards.
The rewards persist across save files, so if you want them, you can make a savefile specifically for the purpose of getting them.

[Mookyjooky]

there is also a true ending clock