diff --git a/src/Entity.h b/src/Entity.h
index 2079c9c..4231cbe 100644
--- a/src/Entity.h
+++ b/src/Entity.h
@@ -11,9 +11,9 @@
 ////////////////////////////////////////////////
 // Entity
 //
-#define EntityFlag_Collision 1
-#define EntityFlag_Overlap 2
-#define EntityFlag_Light 4
+#define EntityFlag_Collision 0x00000001
+#define EntityFlag_Overlap 0x00000002
+#define EntityFlag_Light 0x00000004
 #define EntityFlag_BlockTop 0x00000100
 #define EntityFlag_BlockRight 0x00000200
 #define EntityFlag_BlockBottom 0x00000400
diff --git a/src/GameLib.c b/src/GameLib.c
index 464bbb1..b9212b2 100644
--- a/src/GameLib.c
+++ b/src/GameLib.c
@@ -121,6 +121,13 @@ void GameLib_CheckSize() {
 //
 // Adds an entity to the game.
 void GameLib_AddEntity(Entity e) {
+	// Avoid duplications
+	for (int i = 0; i < g_NumEntities; i++) {
+		if (g_Entity[i] == e) {
+			return;
+		}
+	}
+
 	if (g_NumEntities >= g_NumEntitiesAllocated) {
 		Entity *entity_aux;
 		int *entity_flag_aux;
@@ -162,6 +169,23 @@ void GameLib_AddEntity(Entity e) {
 	Entity_Init(e);
 }
 
+/////////////////////////////
+// GameLib_RemoveEntity
+//
+// removes the entity.
+int GameLib_RemoveEntity(Entity e) {
+	int i;
+	for (i = 0; i < g_NumEntities; i++) {
+		if (e == g_Entity[i]) {
+			// Mark to forget
+			g_EntityFlag[i] = -2;
+			g_EntitiesCompactate = 1;
+			return (i);
+		}
+	}
+	return (-1);
+}
+
 /////////////////////////////
 // GameLib_UnrefEntity
 //
diff --git a/src/GameLib.h b/src/GameLib.h
index 002d378..2cc7929 100644
--- a/src/GameLib.h
+++ b/src/GameLib.h
@@ -35,6 +35,12 @@ void GameLib_CheckSize();
 // Adds an entity to the game.
 void GameLib_AddEntity(Entity e);
 
+/////////////////////////////
+// GameLib_RemoveEntity
+//
+// removes the entity.
+int GameLib_RemoveEntity(Entity e);
+
 /////////////////////////////
 // GameLib_UnrefEntity
 //