Upvote:3
Translating/summarizing from the page you linked to:
In Dutch “retour” means return so you can certainly go back to your point of origin with the same ticket but it's not a day ticket (i.e. you cannot travel freely on the whole network, unlike many German group tickets).
The main conditions are:
Until now, it's a temporary offer, running until August 2014 for travels before October 2014 (I write “until now” because it's been extended once and I imagine it could become a permanent things or maybe a recurring offer).
Note that Dutch railway cards offer a somewhat unusual discount (at least compared to other countries I am familiar with): Under some conditions yearly card holders can take up to 3 other travellers with them with a 40% discount (it's called Samenreiskorting). So if you are travelling in a group with a Dutch resident, you might want to ask them about it, it can also be an easy way to save money.