Thanks Emy! I'll look into 8-way movement.
Oh nice catch re. the sound! You're right, the birds and the lofi music only seem to be coming from the left - I hear it in the browser version and also when I play the game here on my laptop. Unfortunately not sure how to fix it! Inside Godot editor the sound works fine. I've tried reimporting the audio files with "forced mono" but that still hasn't fixed it.