Thank you so much for the detailed feedback :)
Visual clarity is something that has been mentioned a lot when people are critiquing my game and I completely agree. I was trying to mostly stick to the same four colours because I think it looks nice, but you're right that it's hard to balance that with readability. Maybe since enemies are red, and buttons are blue, I could have used more different colours to highlight the player and flag?
I also agree that it's hard to tell the enemies apart. I really struggled to work out what the enemies should even be, so I picked boring shadowy things, but given more time I would have been more creative, which would have also made them more visually distinct from one another.
I would also have liked to use vision cones to more clearly indicate where enemies are facing now, and where they will face next.
Your game is so creative! You presented the mechanic of managing two things at once in a very interesting way. The two screens reminded me of the Nintendo DS. The graphics are also very minimalist and cool.