diff --git a/.eslintrc.cjs b/.eslintrc.cjs
index 864592e7..d8f92ac8 100644
--- a/.eslintrc.cjs
+++ b/.eslintrc.cjs
@@ -26,6 +26,7 @@ module.exports = {
     'plugin:react/recommended',
     'plugin:react-hooks/recommended',
     // 'plugin:@react-three/recommended',
+    'plugin:valtio/recommended',
     'plugin:prettier/recommended', 
     // Enables eslint-plugin-prettier and eslint-config-prettier. 
     // This will display prettier errors as ESLint errors.
diff --git a/.nvmrc b/.nvmrc
index 0828ab79..9a2a0e21 100644
--- a/.nvmrc
+++ b/.nvmrc
@@ -1 +1 @@
-v18
\ No newline at end of file
+v20
diff --git a/package.json b/package.json
index b851532d..fe8dd677 100644
--- a/package.json
+++ b/package.json
@@ -56,6 +56,7 @@
     "eslint-plugin-react": "^7.34.1",
     "eslint-plugin-react-hooks": "^4.6.0",
     "eslint-plugin-react-refresh": "^0.4.6",
+    "eslint-plugin-valtio": "^0.6.3",
     "fast-json-patch": "^3.1.1",
     "is-hotkey": "^0.2.0",
     "jest": "^29.7.0",
diff --git a/yarn.lock b/yarn.lock
index d7e537e3..39a09aa1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2736,6 +2736,11 @@ eslint-plugin-react@^7.34.1:
     semver "^6.3.1"
     string.prototype.matchall "^4.0.10"
 
+eslint-plugin-valtio@^0.6.3:
+  version "0.6.3"
+  resolved "https://registry.npmjs.org/eslint-plugin-valtio/-/eslint-plugin-valtio-0.6.3.tgz#23b2855d682d225fc614fde4f619c23a47839f5e"
+  integrity sha512-s1Ttxcb70pzW5NU28DQ+bUy84ohhQApzuP3ZZeZF7y3nQJlCjh3KRceXvxhf9p+1fTBXcl3psLjNVchk8NetAw==
+
 eslint-scope@^7.2.2:
   version "7.2.2"
   resolved "https://registry.npmjs.org/eslint-scope/-/eslint-scope-7.2.2.tgz#deb4f92563390f32006894af62a22dba1c46423f"
diff --git a/zss/gadget/components/tape.tsx b/zss/gadget/components/tape.tsx
index 74249e8e..9acf50cd 100644
--- a/zss/gadget/components/tape.tsx
+++ b/zss/gadget/components/tape.tsx
@@ -114,14 +114,23 @@ export function TapeConsole() {
   // input & selection
   const visiblerange = width - 3
   const inputindex = (height - 1) * width + 1
-  const hasselection = ispresent(selection)
-  const ii1 = hasselection ? Math.min(selection, cursor) : cursor
-  const ii2 = hasselection ? Math.max(selection, cursor) : cursor
-  const iic = ii2 - ii1
-
   const inputstate = inputbuffer[inputbufferindex]
+
+  let ii1 = cursor
+  let ii2 = cursor
+  let hasselection = false
+  if (ispresent(selection)) {
+    ii1 = Math.min(cursor, selection)
+    ii2 = Math.max(cursor, selection)
+    if (cursor !== selection) {
+      --ii2
+      hasselection = true
+    }
+  }
+
+  const iic = ii2 - ii1 + 1
   const inputstateselected = hasselection
-    ? inputstate.substring(ii1, ii2 + 1)
+    ? inputstate.substring(ii1, ii2)
     : inputstate
 
   // draw input line
@@ -130,7 +139,9 @@ export function TapeConsole() {
 
   // draw selection
   if (hasselection) {
-    applycolortoindexes(inputindex + ii1, inputindex + ii2, 15, 8, context)
+    const p1 = inputindex + ii1
+    const p2 = inputindex + ii2
+    applycolortoindexes(p1, p2, 15, 8, context)
   }
 
   // draw cursor
@@ -146,6 +157,7 @@ export function TapeConsole() {
       count,
       insert,
     )
+    return inputbuffer[inputbufferindex]
   }
 
   function trackselection(index: number | undefined) {
@@ -161,7 +173,7 @@ export function TapeConsole() {
   function deleteselection() {
     setcursor(ii1)
     setselection(undefined)
-    inputstatesetsplice(ii1, iic)
+    return inputstatesetsplice(ii1, iic)
   }
 
   return (
@@ -176,14 +188,21 @@ export function TapeConsole() {
           <UserInput
             MENU_BUTTON={(mods) => tapesetmode(mods.shift ? -1 : 1)}
             MOVE_UP={() => {
-              setinputbufferindex(
-                clamp(inputbufferindex + 1, 0, inputbuffer.length - 1),
-              )
+              const ir = inputbuffer.length - 1
+              const index = clamp(inputbufferindex + 1, 0, ir)
+              setselection(undefined)
+              setinputbufferindex(index)
+              setcursor((inputbuffer[index] ?? '').length)
             }}
             MOVE_DOWN={() => {
-              setinputbufferindex(
-                clamp(inputbufferindex - 1, 0, inputbuffer.length - 1),
-              )
+              // TODO: we should actually be copying history items into an active buffer on edit ?
+              // so instead of overwriting the historyical entry
+              // we copy to our mutable entry before continuting
+              const ir = inputbuffer.length - 1
+              const index = clamp(inputbufferindex - 1, 0, ir)
+              setselection(undefined)
+              setinputbufferindex(index)
+              setcursor((inputbuffer[index] ?? '').length)
             }}
             MOVE_LEFT={(mods) => {
               trackselection(mods.shift ? cursor : undefined)
@@ -195,12 +214,17 @@ export function TapeConsole() {
             }}
             OK_BUTTON={() => {
               const invoke = hasselection ? inputstateselected : inputstate
-              setinputbuffer([invoke, ...inputbuffer])
-              setinputbufferindex(0)
-              setcursor(0)
-              setselection(undefined)
-              setinputbuffer(['', ...inputbuffer])
-              vm_cli('tape', invoke, gadgetstategetplayer())
+              if (invoke.length) {
+                setinputbuffer([
+                  '',
+                  invoke,
+                  ...inputbuffer.slice(1).filter((item) => item !== invoke),
+                ])
+                setinputbufferindex(0)
+                setcursor(0)
+                setselection(undefined)
+                vm_cli('tape', invoke, gadgetstategetplayer())
+              }
             }}
             keydown={(event) => {
               const { key } = event
@@ -249,7 +273,7 @@ export function TapeConsole() {
                               if (hasselection) {
                                 inputstatesetsplice(ii1, iic, text)
                                 setselection(undefined)
-                                setcursor(ii2)
+                                setcursor(ii1 + text.length)
                               } else {
                                 inputstatesetsplice(cursor, 0, text)
                                 setcursor(cursor + text.length)
@@ -269,18 +293,18 @@ export function TapeConsole() {
                     }
                   } else if (mods.alt) {
                     // no-op ?? - could this shove text around when you have selection ??
-                    // or jump by 10 ?
+                    // or jump by 10 or by word ??
                   } else if (
                     key.length === 1 &&
                     inputstate.length < visiblerange
                   ) {
                     if (hasselection) {
-                      setcursor(ii2)
+                      inputstatesetsplice(ii1, iic, key)
                       setselection(undefined)
-                      inputstatesetsplice(ii1, ii2, key)
+                      setcursor(ii1 + 1)
                     } else {
+                      inputstatesetsplice(cursor, 0, key)
                       setcursor(cursor + 1)
-                      inputstatesetsplice(cursor, cursor, key)
                     }
                   }
                   break
diff --git a/zss/lang/ast.ts b/zss/lang/ast.ts
index ca6601d7..93aa43bb 100644
--- a/zss/lang/ast.ts
+++ b/zss/lang/ast.ts
@@ -15,7 +15,7 @@ function addRange(node: CodeNode | undefined): OffsetRange | undefined {
   }
 
   const offsets: (OffsetRange | undefined)[] = [
-    { start: node.startOffset, end: node.endOffset || 0 },
+    { start: node.startOffset, end: node.endOffset ?? 0 },
   ]
 
   Object.keys(node).forEach((name) => {
@@ -33,10 +33,10 @@ function addRange(node: CodeNode | undefined): OffsetRange | undefined {
 
   node.range = {
     start: Math.min(
-      ...offsets.filter((item) => item).map((item) => item?.start || 0),
+      ...offsets.filter((item) => item).map((item) => item?.start ?? 0),
     ),
     end: Math.max(
-      ...offsets.filter((item) => item).map((item) => item?.end || 0),
+      ...offsets.filter((item) => item).map((item) => item?.end ?? 0),
     ),
   }
 
diff --git a/zss/lang/transformer.ts b/zss/lang/transformer.ts
index 31aff140..16974d67 100644
--- a/zss/lang/transformer.ts
+++ b/zss/lang/transformer.ts
@@ -26,8 +26,8 @@ export function write(
   chunks: (string | SourceNode)[] | SourceNode | string,
 ) {
   return new SourceNode(
-    ast.startLine || 1,
-    ast.startColumn || 1,
+    ast.startLine ?? 1,
+    ast.startColumn ?? 1,
     GENERATED_FILENAME,
     chunks,
   )
diff --git a/zss/lang/visitor.ts b/zss/lang/visitor.ts
index fbc81d7f..66b9ab05 100644
--- a/zss/lang/visitor.ts
+++ b/zss/lang/visitor.ts
@@ -77,7 +77,7 @@ function asIToken(thing: CstNode | CstElement): IToken {
 
 function asList(thing: ScriptVisitor, node: CstNode[] | undefined): CodeNode[] {
   return (
-    node?.map((item) => thing.visit(item)).filter((item) => item) || []
+    node?.map((item) => thing.visit(item)).filter((item) => item) ?? []
   ).flat()
 }
 
@@ -257,12 +257,12 @@ function getLocation(obj: CstChildrenDictionary): CstNodeLocation {
     })
 
   return {
-    startLine: Math.min(...locations.map((item) => item.startLine || 1)),
-    startColumn: Math.min(...locations.map((item) => item.startColumn || 1)),
-    startOffset: Math.min(...locations.map((item) => item.startOffset || 1)),
-    endLine: Math.max(...locations.map((item) => item.endLine || 1)),
-    endColumn: Math.max(...locations.map((item) => item.endColumn || 1)),
-    endOffset: Math.max(...locations.map((item) => item.endOffset || 1)),
+    startLine: Math.min(...locations.map((item) => item.startLine ?? 1)),
+    startColumn: Math.min(...locations.map((item) => item.startColumn ?? 1)),
+    startOffset: Math.min(...locations.map((item) => item.startOffset ?? 1)),
+    endLine: Math.max(...locations.map((item) => item.endLine ?? 1)),
+    endColumn: Math.max(...locations.map((item) => item.endColumn ?? 1)),
+    endOffset: Math.max(...locations.map((item) => item.endOffset ?? 1)),
   }
 }
 
diff --git a/zss/memory/atomics.ts b/zss/memory/atomics.ts
index d892cdfe..06d640ac 100644
--- a/zss/memory/atomics.ts
+++ b/zss/memory/atomics.ts
@@ -70,10 +70,12 @@ export function listelementsbykind(
         // console.info('no match on name', name)
         return false
       }
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-enum-comparison
       if (ispresent(color) && boardelementcolor(element) !== color) {
         // console.info('no match on color', color)
         return false
       }
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-enum-comparison
       if (ispresent(bg) && boardelementbg(element) !== bg) {
         // console.info('no match on bg', bg)
         return false
diff --git a/zss/terminal/crt.tsx b/zss/terminal/crt.tsx
index a5db6f1a..cfc0150d 100644
--- a/zss/terminal/crt.tsx
+++ b/zss/terminal/crt.tsx
@@ -90,7 +90,7 @@ void mainImage(const in vec4 inputColor, const in vec2 uv, out vec4 outputColor)
     float phase = time + cos(uv.x + uv.y);
     float slowband = (cos(uv.x + uv.y - phase) + 1.0) / 2.0;
     float fastband = (cos(uv.y + time * 0.37) + 1.0) / 2.0;
-    float blankdmix = 0.5 - 
+    float blankdmix = 0.3 - 
       pow(slowband, viewheight * 0.01) * 0.05 - 
       pow(fastband, viewheight * 64.0) * 0.2 - 
       pow(fastband, viewheight * 128.0) * 0.1;