diff --git a/inc/player.h b/inc/player.h
index 5b47114..78a6a8d 100644
--- a/inc/player.h
+++ b/inc/player.h
@@ -7,6 +7,7 @@ struct Player {
 	struct VecF rem;
 	int jump_grace;
 	int jump_buffer;
+	int lock_direction;
 };
 
 void player_init(struct Vec pos);
diff --git a/inc/util.h b/inc/util.h
index d80a265..4e47124 100644
--- a/inc/util.h
+++ b/inc/util.h
@@ -2,3 +2,4 @@
 
 int sign(int);
 float signf(float);
+int abs(int);
diff --git a/src/player.c b/src/player.c
index 22ec922..039c15e 100644
--- a/src/player.c
+++ b/src/player.c
@@ -22,14 +22,17 @@ player_init(struct Vec pos)
 	self.rem = VECFZ;
 	self.jump_grace = 0;
 	self.jump_buffer = 0;
+	self.lock_direction = 0;
 }
 
 void
 player_update(void)
 {
 	const int on_ground = collide_solid(self.pos.x, self.pos.y + 1);
-	const struct Vec dir = VEC(input_down(K_RIGHT) - input_down(K_LEFT),
-	                           input_down(K_DOWN) - input_down(K_UP));
+	struct Vec dir = VEC(input_down(K_RIGHT) - input_down(K_LEFT),
+	                     input_down(K_DOWN) - input_down(K_UP));
+	if (self.lock_direction && dir.x != self.lock_direction)
+		dir.x = 0;
 
 	/* acceleration & friction */
 	if (on_ground && !dir.x) {
@@ -56,6 +59,10 @@ player_update(void)
 	if (!jump(on_ground))
 		walljump();
 
+	/* unlock direction */
+	if (self.lock_direction && abs(self.spd.x) < MAX_WALK_SPEED / 2)
+		self.lock_direction = 0;
+
 	player_move(player_update_rem());
 }
 
@@ -92,6 +99,7 @@ walljump(void)
 		self.jump_buffer = 0;
 		self.spd.y = JUMP_SPD;
 		self.spd.x = wall_adjacent * MAX_WALK_SPEED;
+		self.lock_direction = wall_adjacent;
 		shatter_pos.x +=
 		    (wall_adjacent == 1) ? (-2) : (PLAYER_WIDTH + 1);
 		shatter(shatter_pos.x, shatter_pos.y);
@@ -125,8 +133,8 @@ player_update_rem(void)
 void
 player_move(struct Vec spd)
 {
-	float sign_x = signf(spd.x);
-	const float sign_y = signf(spd.y);
+	float sign_x = signf(self.spd.x);
+	const float sign_y = signf(self.spd.y);
 	if (!sign_x && !sign_y)
 		sign_x = 1.0f;
 
diff --git a/src/util.c b/src/util.c
index 2be5c77..11279d3 100644
--- a/src/util.c
+++ b/src/util.c
@@ -11,3 +11,9 @@ signf(float n)
 {
 	return (n > 0.0) - (n < 0.0);
 }
+
+int
+abs(int n)
+{
+	return (n > 0) ? (n) : (-n);
+}