I talked to some Dink people and they weren't so sure about it being legal to copy Dink 1:1. The project you linked is the modified engine, which indeed has GNU GPL license. But what about the IP itself? I looked around and found nothing. And "it's free" doesn't really mean anything when the author doesn't clarify what he means by that. Is it CC0? Maybe it's free in the sense that I can download and play it without paying, but I'll get a cease and desist letter if I try to make Dink 2 and sell it.
Edit: I think I found out just how free Dink is. http://www.rtsoft.com/forums/showthread ... ce-License
"*** PROTECTING THE DINK SMALLWOOD NAME AND MEDIA FROM BEING EXPLOITED ***
Do NOT use this source to release "Dink 2" or "SuperDink" or any kind of sequel to the original Dink
Smallwood. Releasing this source does not in any way release the rights to the Dink name
or Dink media.
non-profit improvements to the Dink engine are ok, as listed above, otherwise, you need your own name,
story and artwork. (in which case you can charge for it and pretty much do what you want)"
So that's freeware for you. What I could do is play Dink and make something in the spirit of it. Of course, the story, the characters, the artwork has to be different from Dink.