You might once have an idea about a really difficult game design. However, once you let your family and friends tried it, they all failed, thus making you to modify it. But here in Insane Game Jam, we exactly want you to create some insanely hard to beat games! Your skill level on game development doesn't matter. The only thing limiting you is your creativity.
Any! Example:
Unity Engine
Unreal Engine
LÖVE Game Framework
Game Maker Studio 2
However, if possible, HTML5 is recommended instead of .exe files.
Here are some but the final decision will be on us:
No NSFW
No offensive content
Make sure all assets are okay to be used and credit creators if necessary