diff --git a/src/Player.lua b/src/Player.lua
index 8ac3763..8aed642 100644
--- a/src/Player.lua
+++ b/src/Player.lua
@@ -38,6 +38,15 @@ function Player:init(def, level )
     end)
 end
 
+function Player:isMoveAllowed(point)
+    for i,segment in pairs (self.trailSegments) do
+        if segment:pointInSegment(point) then
+            return false
+        end
+    end
+    return true
+end
+
 function Player:changeState(state)
     Entity.changeState(self,state)    
 end
@@ -88,6 +97,7 @@ function Player:onEdge()
 end
 
 function Player:onWalking()
+    -- if position of player collides with its own trail, stop motion
     if #self.trail > 1 then
         table.remove(self.trail)
         table.remove(self.trailSegments)
@@ -113,9 +123,6 @@ function Player:onChangeDirection()
             table.remove(self.trailSegments)
         end
     
-        local k = #self.trailSegments
-        local j = #self.trail + 1
-
         table.insert(self.trail,
             {['x'] = self.x + self.width/2,['y'] = self.y + self.height/2}
         )
diff --git a/src/Segment.lua b/src/Segment.lua
index 5f59725..61fe0ea 100644
--- a/src/Segment.lua
+++ b/src/Segment.lua
@@ -292,3 +292,19 @@ end
 function Segment:insert(list)
     
 end
+
+function Segment:pointInSegment(point)
+    if self.direction == 'up' or self.direction == 'down' then
+        if point[1] <= self.firstPointX + 1 and 
+            point[1] >= self.firstPointX - 1 then
+            return true
+        end
+    else
+        if point[2] <= self.firstPointY + 1 and 
+            point[2] >= self.firstPointY - 1 then
+            return true
+        end
+    end
+
+    return false
+end
\ No newline at end of file
diff --git a/src/entity/Entity.lua b/src/entity/Entity.lua
index 72aac96..63d0b82 100644
--- a/src/entity/Entity.lua
+++ b/src/entity/Entity.lua
@@ -25,6 +25,10 @@ function Entity:changeState(name)
     -- printChangeState to "..name)
 end
 
+-- function Entity:isMoveAllowed(point)
+--     return point.x, point.y
+-- end
+
 function Entity:changeAnimation(name)
     self.currentAnimation = self.animations[name]
 end
diff --git a/src/states/entity/EntityWalkState.lua b/src/states/entity/EntityWalkState.lua
index 9ec19bd..3f71818 100644
--- a/src/states/entity/EntityWalkState.lua
+++ b/src/states/entity/EntityWalkState.lua
@@ -10,32 +10,40 @@ end
 
 function EntityWalkState:update(dt)
     if self.entity.direction == 'up' then
-        self.entity.y = self.entity.y - self.entity.walkingSpeed * dt            
-        if self.entity.y + TILE_SIZE / 2 < LEVEL_RENDER_OFFSET_TOP - 2  then
-            self.entity.y = self.entity.y + self.entity.walkingSpeed * dt
-            Event.dispatch('back-to-wall')        
-            self.entity:changeState('edge')
+        if self.entity:isMoveAllowed({self.entity.x, self.entity.y - self.entity.walkingSpeed * dt}) then
+            self.entity.y = self.entity.y - self.entity.walkingSpeed * dt            
+            if self.entity.y + TILE_SIZE / 2 < LEVEL_RENDER_OFFSET_TOP - 2  then
+                self.entity.y = self.entity.y + self.entity.walkingSpeed * dt
+                Event.dispatch('back-to-wall')        
+                self.entity:changeState('edge')
+            end
         end
     elseif self.entity.direction == 'down' then
-        self.entity.y = self.entity.y + self.entity.walkingSpeed * dt
-        if self.entity.y + TILE_SIZE / 2  > VIRTUAL_HEIGHT - LEVEL_RENDER_OFFSET + 2 then
-            self.entity.y = self.entity.y - self.entity.walkingSpeed * dt
-            Event.dispatch('back-to-wall')
-            self.entity:changeState('edge')
+        if self.entity:isMoveAllowed({self.entity.x, self.entity.y + self.entity.walkingSpeed * dt}) then
+            self.entity.y = self.entity.y + self.entity.walkingSpeed * dt
+            if self.entity.y + TILE_SIZE / 2  > VIRTUAL_HEIGHT - LEVEL_RENDER_OFFSET + 2 then
+                self.entity.y = self.entity.y - self.entity.walkingSpeed * dt
+                Event.dispatch('back-to-wall')
+                self.entity:changeState('edge')
+            end
         end
     elseif self.entity.direction == 'right' then
-        self.entity.x = self.entity.x + self.entity.walkingSpeed * dt
-        if self.entity.x + TILE_SIZE / 2 > VIRTUAL_WIDTH - TILE_SIZE / 2 + 2 or self.entity.previousdirection == 'left' then
-            self.entity.x = self.entity.x - self.entity.walkingSpeed * dt
-            Event.dispatch('back-to-wall')
-            self.entity:changeState('edge')
+        if self.entity:isMoveAllowed({self.entity.x + self.entity.walkingSpeed * dt, self.entity.y}) then
+            self.entity.x = self.entity.x + self.entity.walkingSpeed * dt
+            if self.entity.x + TILE_SIZE / 2 > VIRTUAL_WIDTH - TILE_SIZE / 2 + 2 or self.entity.previousdirection == 'left' then
+                self.entity.x = self.entity.x - self.entity.walkingSpeed * dt
+                Event.dispatch('back-to-wall')
+                self.entity:changeState('edge')
+            end
         end
     elseif self.entity.direction == 'left' then
-        self.entity.x = self.entity.x - self.entity.walkingSpeed * dt
-        if self.entity.x < 0 or self.entity.previousdirection == 'right' then
-            self.entity.x = self.entity.x + self.entity.walkingSpeed * dt
-            Event.dispatch('back-to-wall')
-            self.entity:changeState('edge')
+        if self.entity:isMoveAllowed({self.entity.x - self.entity.walkingSpeed * dt, self.entity.y}) then
+            self.entity.x = self.entity.x - self.entity.walkingSpeed * dt
+            if self.entity.x < 0 or self.entity.previousdirection == 'right' then
+                self.entity.x = self.entity.x + self.entity.walkingSpeed * dt
+                Event.dispatch('back-to-wall')
+                self.entity:changeState('edge')
+            end
         end
     end
     if love.keyboard.isDown('left') then
diff --git a/src/states/game/PlayState.lua b/src/states/game/PlayState.lua
index f0e28cc..2f50ec6 100644
--- a/src/states/game/PlayState.lua
+++ b/src/states/game/PlayState.lua
@@ -24,6 +24,7 @@ function PlayState:update(dt)
     self.level:update(dt)
     self.player:update(dt)
     self:updateBalls(dt, self.level)
+    self:checkEndLevel(self.level)
 end
 
 function PlayState:render()
@@ -81,6 +82,18 @@ function PlayState:updateBalls(dt, level)
     end
 end
 
+function PlayState:checkEndLevel (level)
+    if #self.balls <= 0 then
+        -- game over - reset level
+        self:gameOver()
+    end
+
+    -- check perimeter of level, if low enough, create new level move on to the next stage
+    if level:getPerimeter() < 500 then
+        self:nextStage()
+    end
+end
+
 function PlayState:renderBalls(dt)
     for k,ball in pairs(self.balls) do
         ball:render()