Nice CRT effect using a CSS animation!
That’s exactly what I meant when I said half the page was lopped off.
Perhaps rotate your phone?
It is irritating when pages block zoom (sometimes intentionally but usually as a side effect of working around sizing oddities in some devices/browsers/versions) but here you may have all you need to solve the problem.
Unless you have a smaller device and it is still too wide in landscape orientation.
Certain parts of the past are not worth emulating :)
Making a silly effect on a website to evoke a nostalgic feeling doesn't really have to be accurate, and it'd probably be near-impossible to accurately represent the subtleties of a CRT display without compounding them with the subtleties of LCDs, especially so when the LCDs an end user will be using is an unknown.
Found it after inspecting the site to see how it was done.