I have the anthology through GOG, but wanted to try them on my phone. Which file(s) do i need to upload, the one called "_ZORK1" looks suspiciously small?

While I admit I don't know anything about loading them onto a phone, I will point out that this is an all text adventure game from about 1980. It's file size will probably inevitably look suspiciously small to anyone used to the games of even 20 years ago. At the time, the whole game had to fit on a single 5.25" diskette.

I'm not trying to sound condescending here, but you should know what kind of games you will be getting if you play most of Infocom's old catalog. Even the few games with substantial graphics at the end will be most heavily text driven with stationary graphics. My view is that they still might be worth playing, though, of course, that's partially nostalgia talking, but not everyone today will feel that way.