diff --git a/readme.md b/readme.md
index b75159b..5bae882 100644
--- a/readme.md
+++ b/readme.md
@@ -43,15 +43,13 @@ if (src.match(/^(file|https)?:\/\/|^\/\//)) {
 ## known bugs
 
 * new tiles can be duplicates
-    * take a different approach
 
 ## to do
 
 * allow user to save output as image, or tweet it :) 
     * *user can currently right-click -> Save As but the 128x128 size is not great*
-* implement slider (*always use existing tiles* -> *always create new tiles*) (representing 0-64 threshold for # of common pixels)
 * re-style the damn thing
-* reorganise the page layout for a more logical workflow
+    * inc. mobile styles
 * animate animated tiles 
 * profile script performance and optimise where most needed
 * make brightness slider trigger redraw every so often while being dragged, instead of waiting until drag stop
@@ -72,3 +70,4 @@ if (src.match(/^(file|https)?:\/\/|^\/\//)) {
 * optionally add inverted versions of existing tiles if they are a better match
 * make new tiles out of fragments of existing tiles instead of directly copying from bitmap
 * allow user to zoom out so the image is letterboxed/windowboxed/etc.
+* break up rendering into separate preview and output modes (would be good to have a throttled preview for brightness slider adjustments and then a debounced tile render)
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