OMG EVERYTHINGS A RIP OFF OF EVERYTHING!!!
Tell me, which do you like better? Doom? Quake? CoD? MW? Are they Rip offs of each other? OMG YES you know why!?!?! CAUSE ITS A FPS!!!!!! SHOCK HORROR!!!
Tell me, which do you like better? Escape from Monkey Island? Sam and Max? Other Point and click adventure games using the same damn system!!?!?!?!?!?
If you know anything about game design, there is nothing close to originality any more. Everythings been done before in some way or form, there will always be an idiot that points at two games and says, OMG RIPOFF!!!!, without knowing anything about it. Minecraft and Terraria for example. Both have the same idea, destroy/collect blocks from the world to build constructions out of said blocks. BUT its those little things that make it different that define it. Knowing what inspires a game, and causes it to grow and become something of its own does not make it a rip off. Making something thats a direct copy of said game is...
Want a REALLY GOOD example of a Ripoff???
http://www.neoseeker.com/news/18218-farmville-creator-zynga-caught-ripping-off-indie-developer-with-new-ios-title/There we go, theres your rip off. A game that is exactly the same from the ground up. Nothing changed except the "Creator" and the graphics and prob the method on which money is made from it.
Towns is not a Rip Off of DF, its inspired and may have started out very similar until the Dev started working on how he wanted to advance things. Thus what it has become now...