Thanks Manupix! I'm updating it now with the mirrored image. This isn't really what I'm working on now though, so I don't think I'll draw a new one from scratch. I also want to keep the original number of frames from wolf3d.

everything should be hand-pixelled: this is to be understood as every pixel position and color should be under control. This means that copy-pasting-mirroring is ok, although not necessarily artistically motivated. Any tool the effect of which is perfectly predictable on every pixel is ok.

What is not ok are tools that don't allow that pixel-level control, such as blurs, noise filters, gradients, auto anti-aliasing, soft brushes, burn & dodge.

Your flame is already very symmetrical, so mirroring it might not change much. It should not be too difficult to draw 3 or 4 different flames from scratch!

You can also link to a different version of a piece in the description, if you are in doubt of its validity.

 Yeah, I originally used the mirror image of the flame every second time to make it move. I took them out because I read that everything should be hand-pixelled. Maybe I'll do that some day.

I agree that it could be smoother also, though I can't add more frames. (only three frames when a dog dies in  the game)

It looks really good :) although i must say it would look better if the flame moved and the animation was a bit smoother