Music is awesome. 

The main game is a bit too long at the start. Might be a good idea to have it start with a low goal (5 diamonds) and then ramp up the difficulty and goal with each level.

Also I think making the main character a slightly different color than the enemies and arena will help make him pop

Good job!

I played your game on stream, here is the VOD: https://www.twitch.tv/videos/1839314176

I discuss how you can improve the visuals in the video above. Basically, posterize a greyscale texture then colorize it. Using a posterize filter on color textures usually results in muddy textures and colors.

This map layout is matching pacman. Would appreciate more originality as well.