Any other equation from physics would impress me more than knowing E = mc². Even something basic as F = ma.

Not OP, but I remember I when I was a kid I enjoyed playing Vector TD, so I tried playing Vector TDX, but it was way harder. I couldn’t figure out how to beat the first couple waves.

I thought that was exactly how copyright works. It is infeasible to keep track of every infringement, so a policy like that is unenforceable.

Also its not out of the question that those myriad of tetris clones each secured some sort of agreement with the tetris company.