Likely .NET (C#) based on common "clicker" utility patterns.
Look for the main logic in the Form or Program classes. rageclicker.zip
Use Cheat Engine to find the memory address for the "Click Count" and manually set it to 999,999. Likely
A hidden conditional branch that only triggers if a specific (impossible) "click count" is reached. rageclicker.zip
Check for suspicious strings or network calls. In many "clicker" challenges, the flag is hidden in: An unused resource file. An obfuscated string constant.