diff --git a/src/collide.c b/src/collide.c
index 7709b26..87d1cac 100644
--- a/src/collide.c
+++ b/src/collide.c
@@ -18,6 +18,9 @@ uint8_t collide_point(Vec point, const Level *level, uint layer_id) {
 	}
 }
 
+/* TODO: 'collide{right,left,up,down} are a bad idea, should replace all
+ * of these for by an unique function i.e. 'player_collide'.
+ */
 bool collide_right(Player *player, Vec position, const Level *level, uint layer_id) {
 	Vec pos;
 	vec_cpy(&pos, position);