good job on makeing your first game;
i think it's normal to be everybody's first game bad, and you only had 3 days so it must have been way harder;
i think most begginers only care about codeing but i think that the visuals matter more;
i think you should try out art jams too and try to find a good art style;
i recommend this video, i think it's good for begginers:
also one of the most important things are the colors, and for colors i use a website called: https://lospec.com/palette-list;
and also i think you should start with a gameboy palette or a 3 colored palette so you don't need to select from so much color;
good luck on your game dev journey;