In demoscene nomenclature, an "intro" is a demo with a sizelimit. This was entered in the demo compo, ergo "no size limit".

With file size, most democoders go all the way, both ways. By that I mean that if they choose a sizelimit category, they squeeze out every last byte, and if they don't, most don't care about filesize at all. There's demos these days that are many times bigger than an acceptable video recording would be because nobody bothered to eg compress the assets, it includes an entire game engine, etc. Like 800MB for a 3 minute audiovisual show. Kinda ridiculous but it's just.. well, call it either laziness or focused pragmatism :-) Gotta get that prod out before the deadline!

The Razor1911 zip[1] is 30MB, which actually is very much on the small side for a current-day demo.

[1] https://www.pouet.net/prod.php?which=105954 has a download link