You have some risk in your composition. You were willing to have a worms eye view, which can be challenging. You also show signs of entropy on the Dragonzord, with some scratches on its metallic skin. You also have a complex pose on the Green Ranger although it seems overly used. Your proportions are very accurate and you payed good attention to details. The hand looks very nice as well. One of the big things that can be improved is separating the Dragonzord from the Green Ranger. They blend in with each other. You can make the line more defined or add a stronger shadow on the Dragonzord to separate the two. You can also look into atmospheric perspective. Think of something to help the viewers see them in different layers in space.

Nice work.

Nice! The detail looks spectacular. You did a great job of getting the metal texture down.

I think one thing that made the original piece stand out so much was the contrast brought about by the purple in the background. Your piece might be improved by bringing some of that purple back in.

Another thing that might improve it is if there was a little more contrast in the green parts. Making the dark green parts darker and the light parts lighter. It might also look good if there was some hints of yellow in the lighter green areas and hints of blue in the dark green. Also, if a bit of the colors from the sunset were reflected in the metal, it might add a nice touch.

Honestly, I can't find anything else to give as critique or tips here! Nicely done!