Going to give a talk about Espruino. What should I mention?

Wow, great! Maybe embedded JS work does turn you into a lumberjack...

Seems really good, and loads of demos packed in too! A few small things I noticed...

• The debugger highlights the line it stopped on in functions - except when they're defined inline as in your example, so there's no line highlighting and it gets a bit confusing. I'll see if I can fix that but if you want a better demo you could define the function separately :)
  
• The assembler's actually built into the IDE, so it works offline (hardly a big deal).
  
• The C and compiled JS is an online service as you said, while JS compilation is limited, the C compiler is complete (it's just GCC).
  
• Puck.js has an IR transmitter, but no receiver built-in I'm afraid. Getting it to receive signals only requires a ~$1 part though.