The ideas behind these demons are nice, the design of the fourth one on the bottom row is very appealing to me. And the shading and highlighting on these demons is top notch. But there are verious problems which can stick out like a sore thumb when pointed out. The first problem I imediately noticed was the random grey pixel to the right of 1-2. as well as 4-2 (and 2-1) having lefover white from their original canvas on them.
Another problem I noticed was the abundance of jaggies on these demons (take 1-2's bat or 5-1's tail for example). and the selective outlining is inconsistent (the outline shouldn't be shaded as it's own entity, where the sprite is shaded should dictate where the outline is shaded). and the lighter parts of the outline blend in with the base tone on a lot of the demons (4-2 and 5-2 being offenders of this). 1-1 dosen't even have sel-out's. There are also a couple of demon specific critiques. For example I2-2's mandibles don't have outlines, making theme seem like just designs instead of being seperate from the body. But most of them are nitpicks more than critiques
Please don't take this personally, I find a lot to like in these sprites. It's just there are a couple of flaws that bring them all down.
Thanks for the feedback, I appreciate it. Always good to see some constructive criticism; i'll try my best to fix 'em in the future!