I really like the overall mood you establish with this piece, and the motifs you have are nice. I do agree that it's a bit repetitive, maybe you could try playing those motifs you have in different octaves throughout the piece? I could see the motif played down one octave having a very deep, grounded feeling reminiscent of a forest, and in one octave higher, having a very mystical feel. You could also try diversifying your left hand as well. Move those octaves up and down, try other intervals like 5ths and 6ths, or maybe just have one note playing at times. Try experimenting with your ideas, and I think your piece will become even more atmospheric!