The colour palette was mainly inspired by my initial interpretation of early concepts of the game's vision—a lonely tennis robot inexplicably misplaced within a barely-lit clocktower must fight its way through other autonomous yet aggressive foes to escape.
While the yellow doesn't have its originally intended effect of conveying the little bit of outside light that does manage to creep into the facility (rather it now mainly allows for contrast between obstacle and otherwise), the purple still stands to highlight both the generally dark surroundings and mysterious circumstances the protagonist and player are subjected to.