diff --git a/Jumpy.Shared/Player.cs b/Jumpy.Shared/Player.cs
index 2a8edcf..182502f 100644
--- a/Jumpy.Shared/Player.cs
+++ b/Jumpy.Shared/Player.cs
@@ -44,6 +44,8 @@ namespace Jumpy {
       bool standingOnGround = false;
       // TODO: implement https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm
       // e.g. http://members.chello.at/~easyfilter/bresenham.html
+      // TODO: currently player doesn't fall through a gap one tile wide; presumably this will
+      // be fixed by switching to a line-rasterization approach.
       foreach (var rect in collisionTargets) {
         playerBbox = Bbox(position);