Whow, wow, what now? That is the harshest criticism I've gotten... cool!
Ha, really? Don't take this the wrong way, but you probably haven't been criticised very much
Anyway, which side of this rock looks better? The left side is yours, the right is yours with smooth outlines.
If you want jagged edges, you need to make them a little more jagged and use antialiasing (not necessarily with transparency, but certainly with the nearby colors).
(unrelated: "public domain" does not mean what you think it means. a public domain tileset would be one for which no credit or permission whatsoever is required, and that could be modified in any way while still giving no credit. beethoven's music, for example, is public domain. most of kevin macleod's music, on the other hand, is under a creative commons license, but is not public domain: you are violating the license terms if you use or modify it without giving credit. your tileset is neither, since you say you do not allow modifications or use without permission.)