I really like her design, but also agree with what other said: it bothers me how base stays almost the same through all stages. Hair and things like skin color give lots of options to add changes into knuffel (and it's the whole knuffel that should evolve in general) and playing with elements like hair make evolving much easier.
You can also try working with what you have already. Her second stage does need at least one more visable change or new, big element. You can try balancing elements you have already, for example:
1-2: adding 3rd stage shoes to make change bigger
2-3: adding more details to shoes and forehead eyes + something more?
3-4: adding basic shape of gloves + something more?
and then think about something new you can add to final stage (web hanging from spider legs for example, richer hair ornament) . Basically, right now she looks like if you could just kick out second stage and then all she would need is adding fifth one.
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