Hi! This would look awesome in a crt. But there are some problems:
The pixels seems to be missaligned, you can notice there are different size pixels even at high resolutions.
A 15 khz crt can't show resolutions >288p so you can use base resolution like 480x270, and resize to the nearest neighbor: 960x540, 1920x1080... or 426x240-> 852x480, 1278x720, 1704x960...
This way it would display right in low and high resolutions
Also the ui is one size (+-480x270)and the game itself another one (+-640x360)