new options, and hot keys and readme clean up (#148)

src/core/Game.lua

@@ -246,7 +246,11 @@ end
 function Game:zoomStep(delta)
   local Zoom = require("src.render.Zoom")
   if not Zoom.gateOK(self.stack:top(), self.overworld) then return end
-  Zoom.step(delta, Renderer:fitScale())
+  local offset = Zoom.step(delta, Renderer:fitScale())
+  if self.save and self.save.options then
+    self.save.options.zoom = offset
+    self:writeOptions()
+  end
 end
 
 function Game:wheelmoved(_, dy)
@@ -320,6 +324,14 @@ function Game:keypressed(key)
       self:writeOptions()
     end
     return
+  elseif key == "4" then
+    -- cycle ZOOM through every integer level (survey → FIT → close-up → wrap)
+    local Zoom = require("src.render.Zoom")
+    if Zoom.gateOK(self.stack:top(), self.overworld) then
+      self.save.options.zoom = Zoom.cycle(Renderer:fitScale())
+      self:writeOptions()
+    end
+    return
   elseif key == "5" then
     -- cycle GBC FX OFF → 1 → 2 → 3 → 4 (unlit-GBC ladder); always on
     -- desktop.  Mobile refuses the present shader (issue #136).
@@ -445,6 +457,8 @@ function Game:applyOptions(opts)
   if Sound.applyOptions then Sound.applyOptions(opts) end
   require("src.render.PaletteFX").applyOptions(opts)
   require("src.render.Tilt").applyOptions(opts)
+  require("src.render.Zoom").applyOptions(opts)
+  require("src.render.TileRenderer").applyOptions(opts)
   -- returns true when a persisted GBC FX level was cleared on mobile
   local gbcCleared = require("src.render.GBCFX").applyOptions(opts)
   require("src.core.VideoMode").applyOptions(opts)

src/core/SaveData.lua

@@ -186,10 +186,14 @@ function SaveData.defaultOptions()
     musicFilter = 0,
     -- logic fast-forward multiplier; audio is unaffected (GameSpeed.lua)
     speed = 1,
-    -- port display options (OptionsMenu / hotkeys 2/3/5)
+    -- port display options (OptionsMenu / hotkeys 2/3/4/5)
     colors = "gbc",
     tilt = 0,
     gbcfx = 0,
+    -- survey zoom offset from window fit scale (0 = FIT); see Zoom.lua
+    zoom = 0,
+    -- OVERWORLD beyond-edge fill: trees | water | black
+    voidFill = "trees",
     -- windowed | borderless (desktop fullscreen); ignored on mobile
     videoMode = "windowed",
     -- hard render frame-rate cap; render-only pacing (issue #88, FrameCap.lua)