I play Simon's Tatham's puzzles from time to time to de-stress. I'm surprised it's not a default function of browsers to be honest - new tabs are such wasted sp

I play Simon's Tatham's puzzles from time to time to de-stress. I'm surprised it's not a default function of browsers to be honest - new tabs are such wasted space. How hard would it be to embed it in the new tab so everyone can enjoy some mental recreation?