Good effort.

Some tips:
+ Wash the parts before you paint them.
+ Consider applying a white undercoat. I never do that, but I know others who do.
+ After painting, allow the paint to dry before applying another coat. The more coats the merrier, especially if you haven't applied an undercoat.
+ Consider applying a spray-on purity seal to protect the paint from abrasions etc.; we did this with the Sabretron 2004 exclusive toys.

My first custom was a repaint of Transmetal Tarantulas as "Vok Hunter Tarantulas." It turned out that Fox Kids TM Tarantulas would become the real "Vok Hunter Tarantulas" (although neither the toy nor character was ever given that title) afterwards. Later I made an "Animé Optimus Prime - a G1 Prime with blue eyes. A year later Takara reissued New Year Special Convoy, a reissue of Goodbye Convoy with... yep... blue eyes.

So here's hoping HasTak will never make an official Animated Nemesis Prime so that your custom remains nice and unique.