How do i shrink pixel art

I'm posting from phone as I'm not in front of Photoshop,..

Perhaps try the mosaic filter before downsizing using nearest neighbour in steps of 50%.

Pixel art is generally best created at final size.

Use image -> image size with resample settings set to " Preserve settings"

you can also try Gigapixel Plugin from Topaz Labs 

it does a great job for image upsizing.

If your using Image>Image Size, do you have Resample set to Nearest Neighbor?

What is the starting size & resolution of your canvas?

What is the target size and resolution?

For games, maybe you should start over with a canvas of required size and resolution.  That way, you don't have to resize it later.  Go to File > New...  see screenshot.

Hope that helps.

If you change the number of Pixels you have for an image you change the images's quality.  If you reduce the number of  pixels you discard some detail you have for the current image. If you increase the number of pixels you need to create detail you do not have for the current images.  In either case the new image created quality will be different then the current image for you either discarded detail or made up detail. You do not gain image quality in either case. Image quality does change that means you loose some image quality.  The exception is if the image is a vector image. The Pixels image generated will be the best quality possible for any given number of pixels that vector image can be rendered with.  So image quality will improve or decrease when it come to Vector images. So if you decrease the number of pixels the Pixels image quality will decrease  for both  raster  and vector images.