If you want to make it look less like a render and more hand drawn, maybe you could try to make the shading more simplified and based on angles without smoothing.
A good example would be the Irkalla Mechs, not just the design, but that the shading is very sharp and they have clear highlights for the edges.
Another idea which would work for a fixed perspective camera, would be darkening/simplifying the palette for everything that is further away from the camera.
Like a lot of platforming sprites do, where the leg furthest away from the camera will be dark, sometimes just a silhouette.
Also the dark background makes it hard to judge though because the darker parts blend into it and the bright parts look blown out.