You can push as much or as little as you like. Usually it's just similarities like the art style or view angle, setting etc. 20% to 80% similar I think works. 20% being you have very little the same. Hope this helps!
Yes thank you I was looking at some and felt I might be able to pull some inspiration from them, specifically was drawn to legend of Kage and thought I could do something in a similar tone but with potentially improved gameplay mechanics and updated graphics