Can I use other game's arts?
I use all kind of pictures I can find. UI & items, I believe they have no copyrights. A character, better not use. But how about a skeleton, a zombie? For example, I can use some tools and get all monster animations in Kingdom Rush, can I use them to do another Tower Defense game? Or other type of games totally irrelevant? How do you judge you crossed the line or not?
In case you like both match-3 game & Fruit Ninja: