Actually, that's quite a simple asset, judging from this picture alone is quite hard. Anyways, are you actually going for this low poly look that older N64 games have or was that by accident? If you're trying to make it look more appealing and modern, you could start by adding details to it, by handpainting some imperfections. I never played Kingdom Hearts before, so I looked at some pictures. The original in game weapon is stylized, I suggest maybe adding some handpainted textures and bump maps. Also, the shader could use a bit more work. Oh by the way, I would be curious with the topology, seems lowpoly, did you use proper topology+subdivision?Or did you directly go with a lowpoly model?