I thought this was interesting, from Discord announcement posts:

>Quick update. The U.S. government raised concerns about the game and Steam has paused the release. March 1st is off the table for now. Will keep you posted.

> Update on the Steam situation. The U.S. Department of Commerce raised concerns with Steam that the game could possibly violate some export control laws. So Steam paused the release. I've researched every law they cited and they definitely don't apply. No video game has ever been subject to these regulations. Microsoft classifies all their games as unrestricted. The physics in my game are intentionally wrong because it's 2D and everything in it comes from Wikipedia and textbooks.

> I'm applying for a formal classification from the Department of Commerce but I've also sent Steam a detailed explanation of exactly how I'm not in violation of any export law. Hopefully they review it and restore the release. If they need the formal classification first it could take a few months.

Couple of months later:

> GOOD NEWS! I have gotten my classification of EAR99 which just means its unrestricted. So we are back on for release!!!!!