I will have to agree with some of the comments here in the past that the marketing of gulden is poor. This is the most likely reason for the low marketcap. Good if you investing in the hope the marketing situation changes. The development is more then good enough as PeterPicker has stated while comparing Gulden to other coins with a higher ranking on coinmarketcap.
Can you send this link to Rijk or whoever runs marketing for Gulden?
Not to do with marketing, I recently found out that a lot of people are forcing the price down as a way to punish the developers for not releasing any news on PoW2 and SegSig because voicing your concerns only gets you banned. The only way to get the developers attention is through driving the price into the ground. With more transparency faith in the market will be restored.