This is awesome! Reminds be of one of my favorite games, Metal Slug.

 so cool !!

 The bouncing light in the front reminds me of metal slug :0

Nice work on this! the second to the bottom one is quite awesome.

 those are sweet

Thanks for your comment! You're right about the white graphics and the semi-transparent layer    I have learn a lot about pixel art since I made those tanks :)

I just thought they were better here in my gallery than on my laptop's hard drive

Nice job overall. A few nitpicks are the white graphics on the 3rd tank. The luminesence is so strong they appear to be floating above the tank. A dull white, maybe even 2 dull whites, (green/ochre tank so a yellowed white is cool too) would set them in and make them appear finer too. Its fine for you still as you have yet to pick up a lot of pixelart related stuff. As I've mentioned before, for now really focus on color, shades, hues, etc. It will help :)

Also, maybe (did not check) the shadows over the wheels on the bottom 2 are a semi-transparent layer. In Pixeljoint where pixel purists and people into the pixels details like that will kill your art. The smaller the piece the more people zoom to inspect + we all tend to zoom regardless. This is easily created with pure pixel work, looks better and makes you better. If not a trans layer then nvm this paragraph.

That said, semi-transparencies are OK in real world settings and in game development. In commission work we all do it because it speeds up production or a project allows it. Its just better to know how its done manually. We do want you to become a pixel nerd and have a kick-ass gallery ;)