Looks like you compensated with your seam allowance to make sure the center of the star was flat, not cupped. This probably caused the rest of the star to be a bit skewed so the setting squares and triangles are off. Having said this, I really don't think it's that bad. You took the time to make sure the inner portions of the star matched exactly (where it meet the brown setting portions), which goes a long way to make it look correct. I would just recut and re-sew the setting pieces to make the quilt come out square and not cut off any of the points. On your next one, you need to be very precise on cutting and maintaining the proper seam allowance. Also, check your angles as you go. I personally think that appliqueing something over the center would just draw the eye towards it.