diff --git a/IDEAS.txt b/IDEAS.txt
index 7b429ba..54f5ece 100644
--- a/IDEAS.txt
+++ b/IDEAS.txt
@@ -11,6 +11,7 @@ These are some ideas about what you can do with this game:
 - Port to GBA.
 - Add OpenGL (or other accelerated) rendering, with true 3D, true color,
   antialiasing, texture filtering etc.
+- Add movement inertia.
 - Improve SW rendering on PC, e.g. use full z-buffer, particle effects etc.
 - Try to add screen space filters, like screen space antialiasing or pixel art
   upscaling algorithms.
@@ -29,6 +30,7 @@ These are some ideas about what you can do with this game:
 - Create an "HD" pack, upscale textures, use more colors, HQ sounds, add
   postprocessing etc.
 - Take the assets and recreate the game in another engine, e.g. the Doom engine.
+- Try to optimize this further, lower resource usage.
 - Take another game, e.g. Freedoom, and recreate it in this engine.
 - Create a script that will create 3D obj models of the levels, to be used in
   Blender etc.