My highest Score in the first Level was 57460 which just surpasses the set score of 57300 (I wanted to proof if its beatable and indeed it is, but on very High Difficulty because, there are much more enemies around which raise the score when beaten)
https://www.youtube.com/watch?v=kPuGsP90oHA
My highest score in a single Playthrough is 784570 (also played on Very Hard Mode)
And my total highest Score (which I know of) is 1573000. In theory (if you play all 4 modes/loops after oneanother a totalscore of over 2000000 (2 million) should be possible without Score Farming.
What is your Max Score?