The main feature of the hidden cell editor is that it has 5 more pages of parts. They are not exactly different parts, but they are remakes of the parts. The last page also only has 4 parts: the 3 eyes and the hidden eye part.
The other pages have parts that function like the normal parts, but look very different!
For example, probosci on later pages have teeth and are thicker, and spikes vary in length. The eyes look the same throughout, however, on the last page there are no new mouths or accessories, just the 3 eyes with an extra hidden eye.