8dir collisiondetection with tweening?!

heres another attempt:

	'angle
	If KeyDown(KEY_UP) And KeyDown(KEY_LEFT) 
		player.angle = 135
	Else If KeyDown(KEY_UP) And KeyDown(KEY_RIGHT) 
		player.angle = 45
	Else If KeyDown(KEY_DOWN) And KeyDown(KEY_LEFT) 
		player.angle = 225
	Else If KeyDown(KEY_DOWN) And KeyDown(KEY_RIGHT) 
		player.angle = 315
	Else If KeyDown(KEY_UP) 
		player.angle = 90
	Else If KeyDown(KEY_DOWN) 
		player.angle = 270
	Else If KeyDown(KEY_LEFT) 
		player.angle = 180
	Else If KeyDown(KEY_RIGHT) 
		player.angle = 0
	End If
	
	'speed
	If KeyDown(KEY_UP) And KeyDown(KEY_LEFT)  'And Not player.detector.detectors[0] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_UP) And KeyDown(KEY_RIGHT)  'And Not player.detector.detectors[2] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_DOWN) And KeyDown(KEY_LEFT)  'And Not player.detector.detectors[5] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_DOWN) And KeyDown(KEY_RIGHT)  'And Not player.detector.detectors[7] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_UP)  'And Not player.detector.detectors[1] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_DOWN)  'And Not player.detector.detectors[6] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_LEFT)  'And Not player.detector.detectors[3] 
		player.speed = player.speed + 0.5
	Else If KeyDown(KEY_RIGHT)  'And Not player.detector.detectors[4] 
		player.speed = player.speed + 0.5
	Else
		player.speed = player.speed / 3
	End If
		
	'limit speed
	If player.speed < 0.5 player.speed = 0
	If player.speed > player.maxspeed player.speed = player.maxspeed
	
	If player.speed > 0
		player.vx = Cos(player.angle)  '* (player.speed * 32) / (1000.0 / Float(update_time)) 
		player.vy = -Sin(player.angle)    '* (player.speed * 32) / (1000.0 / Float(update_time)) 
	Else
		player.vx = 0
		player.vy = 0
	End If
	player.oldx = player.x
	player.oldy = player.y

	'collisions
	ResetCollisions() 
	RenderLayer(World, WorldX, WorldY, WorldZ, player.layer, player.x, player.y, 1) 
	
	Local x:Int
	Local y:Int
	For x = 1 To Abs(Ceil(player.vx)) 
		If player.vx > 0 Then
			If Not CollideImage(player.shadow, player.x + 1, player.y, 0, COLLISION_LAYER_1, 0) 
				player.x = player.x + 1
			Else
				player.x = player.oldx
				player.speed = 0
			End If
		Else
			If Not CollideImage(player.shadow, player.x - 1, player.y, 0, COLLISION_LAYER_1, 0) 
				player.x = player.x - 1
			Else
				player.x = player.oldx
				player.speed = 0
			End If
		End If
	Next
	For y = 1 To Abs(Ceil(player.vy)) 
		If player.vy > 0 Then
			If Not CollideImage(player.shadow, player.x, player.y + 1, 0, COLLISION_LAYER_1, 0) 
				player.y = player.y + 1
			Else
				player.y = player.oldy
				player.speed = 0
			End If
		Else
			If Not CollideImage(player.shadow, player.x, player.y - 1, 0, COLLISION_LAYER_1, 0) 
				player.y = player.y - 1
			Else
				player.y = player.oldy
				player.speed = 0
			End If
		End If
	Next