I took a look at it as well.
I'm not sure what purpose is there for the spine to be cut out? The mobo cut out is much larger than required, as well as the bottom part.
I'd actually leave it solid in this chassis, or use 2mm or thicker aluminum for better structural integrity. I would reduce the size of the cutout and only have the cutout if it serves a purpose.
Those 120mm fan mounts, the long and thin ones, will be really flimsy. Make it one big piece instead of two, or make it a bit bigger with bend.
The green psu bracket looks way too weak. I wouldn't try to make all the brackets and stuff so small. Keep the bends and cuts simple for the techs to manufacture it. I'd make the psu bracket one solid pieces with predefined holes and a solid cutout in the center. It also needs to be attached at at least 3 points.