This Crownland you have linked is a madness of an excellent developer's work, mostly quirks (I guess). According to my knowledge such a fast horizontal scrolling and colourful background is impossible in standard Atari with standard coding.

And it seems those are Polish guys (https://www.atari.org.pl/forum/viewtopic.php?id=4520)

-- EDIT --

I found it: only version for Atari 130XE (i.e. 128KB RAM - this is not the standard, I guess it could run with cartdrige on 65 XL/XE maybe?), year 2006/2007 (fresh :) )