diff --git a/readme.md b/readme.md
index 56a6a06..2148fe7 100644
--- a/readme.md
+++ b/readme.md
@@ -40,6 +40,10 @@ if (src.match(/^(https)?:\/\/|^\/\//)) {
 if (src.match(/^(file|https)?:\/\/|^\/\//)) {
 ```
 
+## bugs
+
+* does not work on ipad (can't scroll to the right?)
+
 ## to do
 
 * make it clear that the user can paste in their own game data
@@ -50,6 +54,7 @@ if (src.match(/^(file|https)?:\/\/|^\/\//)) {
 * 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
+* add up/down arrows to the brightness slider for incremental tweaks
 
 ## could do
 
@@ -66,4 +71,5 @@ 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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+* 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)
+* add 'invert' function?
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