For the past year or so, I've been designing a top-down zombie shooter game. However, after playing a 2d top-down battle royale game, it's given me inspiration to build a similar game. The graphics would be very similar, though there would be new things like building.
I'm trying to decide if this concept is different enough; there's another similar game, though it has different graphics and some other key differences.
I'm wondering at what point two games become too similar, and how to avoid taking too many ideas from one game (a common problem for me).