Space Shooter Mockup :: Pixel Art Detail

stars. maybe i should put less contrast in on those?

I think i know the answer. lol.

I'm being kinda confused about the white/grey things. Is it snow or stars or even projectiles?

Looks quite nice, you've got idea of shading right. If your aim is to be able to draw in the style of conventional shooters (Like Xevious, Gunlock, Raiden etc.), there's need to study designs of spaceships, to look what makes them look cool (like panelling, stripes of different colour and such) and draw them (not necessary on computer) by yourself. Sci-fi illustration, other games will do. You even can get idea or two from design of cars.
For the rest - note how status bar is appearing in arcade game - letters are often have grades of colour, cast some sort of shadow - these tricks make the pic look more professional (but sometimes many details mess things up).

Ok I guess it will never be a real game... but it is fun to look at. But whatever those grey blob things are you bunched them and crammed them in some places while in other areas there is none. It really is nothing special at all