If they are really not suitable you can paint over thema bit to add more "pixelated" feeling (sample provided, adding a bit of outline and shine on the top most car)
Also the artist and the site have a lot copyrigthed material (Marvel/Pixar/Disney...) marked under "Editorial Uses Only"
They claim that you can't not use them in products for with any kind of profit as you will no have the rigths (OK, maybe) but themselves are selling it (Not OK!)
The generic "nice work!" comment is sometimes really helpfull not for the site but for the begginer artist.
It encourages contributions (even if some of them are not that good yet)
http://opengameart.org/content/side-scrolling-character-art-collection
I'm sure that you'll find something there. Or at least something easy enough to edit (adding a gun)
Good hunt!
There is also those other ones
http://opengameart.org/content/isometric-vehicles
http://opengameart.org/content/isometric-vehicles-2
If they are really not suitable you can paint over thema bit to add more "pixelated" feeling (sample provided, adding a bit of outline and shine on the top most car)
Also the artist and the site have a lot copyrigthed material (Marvel/Pixar/Disney...) marked under "Editorial Uses Only"
They claim that you can't not use them in products for with any kind of profit as you will no have the rigths (OK, maybe) but themselves are selling it (Not OK!)
Iffy at best.