just something i'm working on..

[Vipershark]

something i'm doing just for fun. i'm sure this is frowned on here *hides* i didn't want to connect the lower most line on the shoulder armor but with it going straight it didn't look right just stopping..i had a version where it curved around as if the view was at an angle, then saw i was wrong..

High resolution sprites are definitely allowed here.
The only problem I can really see so far is that you seem to be basically drawing over the existing pixels, which won't really give you the look you want. (I've tried)
The shoulder, uh... ball thing... stands out in particular because it's got that really thick outline around it which conveniently happens to match the same thickness that the upscaled pixels are at as well.

Simply drawing over the existing pixels makes your sprite look like it's gone through a bad visual filter or something and looks pretty unnatural.
The only way to really fix it is to basically turn the sprite into a silhouette and then resprite it natively at the higher definition.

Unfortunately, that's a lot easier said than done since at that point you're kind of creating a new sprite anyway...