diff --git a/src/assembler.js b/src/assembler.js
index d054906..c55a0fd 100644
--- a/src/assembler.js
+++ b/src/assembler.js
@@ -127,7 +127,7 @@ function decodeNumericOp(arg) {
 
 /**
  * @param {string} op
- * @param {object} labels // TODO document better
+ * @param {object} labels // TODO - document labels object
  * @param {number} IP
  * @returns {Array<string>} - array of labels
  **/
diff --git a/src/cardiograph.js b/src/cardiograph.js
index 35dc9e9..194ff2b 100644
--- a/src/cardiograph.js
+++ b/src/cardiograph.js
@@ -5,7 +5,7 @@ const CPU = require('./cpu.js');
 const io = require('./io.js');
 
 
-// TODO TEMPORARY - replace with reading STDIN:
+// TODO - replace with reading STDIN:
   const assembler = require('./assembler.js');
   const fs = require('fs');
 
@@ -37,7 +37,7 @@ async function tick() {
 }
 
 function logDisplay() {
-  io.showDisplay(cpu.memory, true); // TODO more compled printing
+  io.showDisplay(cpu.memory, true); // FIXME - display - allow printing hex as well as pretty-printing
 }
 
 function logCPUState() {
diff --git a/src/cpu.js b/src/cpu.js
index 22649de..54df653 100644
--- a/src/cpu.js
+++ b/src/cpu.js
@@ -35,11 +35,11 @@ module.exports = class CPU {
     this.memory.set(machineCode, 0);
   }
 
-  peek() { return; } // TODO
+  peek() { return; } // TODO - implement Peek
 
-  poke() { return; } // TODO
+  poke() { return; } // TODO - implement Poke
 
-  /** @param {Array} info **/ // TODO type info
+  /** @param {Array} info **/ // TODO - document type for 'sourceInfo'
   loadSourceInfo(info) {
     this.dbg.sourceInfo = info;
   }
@@ -54,7 +54,7 @@ module.exports = class CPU {
     this._cycleStartCallbacks.forEach((fn) => fn());
 
     if (this.IP >= this.memory.length) {
-      console.error('HALTING - IP greater than memory size'); // TODO -- should this throw an error instead?
+      console.error('HALTING - IP greater than memory size'); // FIXME - halting the CPU should throw an error instead
       this.running = false;
     } else {
       this.instruction.opcode = this.memory[this.IP];
@@ -68,7 +68,7 @@ module.exports = class CPU {
 
     // Temporary limit as a lazy way to halt infinite loops
     if ((this._cycleLimit > 0) && this.dbg.cycleCounter >= this._cycleLimit) {
-      console.warn('  HALTING - reached cycle limit'); // TODO -- throw error?
+      console.warn('  HALTING - reached cycle limit'); // FIXME - throw error instead
       this.running = false;
     }
 
@@ -164,7 +164,7 @@ module.exports = class CPU {
       let bitSixCarry = 0;
       if ((this.acc & 64) && (lit & 64)) { bitSixCarry = 1; }
       // let overflow = bitSixCarry ^ (this.flags & 8);
-      // FIXME FIXME FIXME
+      // FIXME - re-implement overflow
       // I'm on a plane and can't remember how this works
       let overflow = 0;
       if (overflow) {
@@ -192,7 +192,7 @@ module.exports = class CPU {
       let bitSixCarry = 0;
       if ((this.acc & 64) && (addr & 64)) { bitSixCarry = 1; }
       // let overflow = bitSixCarry ^ (this.flags & 8);
-      // FIXME FIXME FIXME
+      // FIXME - re-implement overflow
       // I'm on a plane and can't remember how this works
       let overflow = 0;
       if (overflow) {
@@ -220,7 +220,7 @@ module.exports = class CPU {
       let bitSixCarry = 0;
       if ((this.acc & 64) && (lit & 64)) { bitSixCarry = 1; }
       // let overflow = bitSixCarry ^ (this.flags & 8);
-      // FIXME FIXME FIXME
+      // FIXME - re-implement overflow
       // I'm on a plane and can't remember how this works
       let overflow = 0;
       if (overflow) {
@@ -248,7 +248,7 @@ module.exports = class CPU {
       let bitSixCarry = 0;
       if ((this.acc & 64) && (addr & 64)) { bitSixCarry = 1; }
       // let overflow = bitSixCarry ^ (this.flags & 8);
-      // FIXME FIXME FIXME
+      // FIXME - re-implement overflow
       // I'm on a plane and can't remember how this works
       let overflow = 0;
       if (overflow) {
@@ -293,7 +293,7 @@ module.exports = class CPU {
     flag_toggle: (flagNum) => {
       if (flagNum === null) {
         console.error('Invalid flag number');
-        process.exit(); // TODO review
+        process.exit(); // FIXME -- throw error instead
       }
       const flagName = this.flagNums[flagNum];
       this.dbg.currentMnemonic = `FTG ${flagName}`;
diff --git a/src/io.js b/src/io.js
index 0bd3b24..ec7f413 100644
--- a/src/io.js
+++ b/src/io.js
@@ -13,7 +13,6 @@ function getKeypadInput(cpu) {
     process.stdin.setRawMode(true);
   }
   process.stdin.on('keypress', (str, key) => {
-    // TODO: is it possible to turn this off again?
     if (key.sequence === '\x03') process.exit();
     let name = key.name.toUpperCase();
     if (name in CFG.keyMap) {