Did you play on a different aspect ratio, like 4:3? It should work fine on bigger ratios like 16:10, 21:9 etc but i know Unity games dont scale well to 4:3 and i'm not sure there's much to do about that.
My screen's aspect ratio is 4:3. A solution to this might be to make the levels smaller, so they fit on a screen with aspect ratio of 4:3.
I'm not sure about sacrificing the game's level design just so people on 4:3 can play it though lol
