Hi @brettkoz good question, and congrats on the game! There are a couple general strategies we have documented here https://excaliburjs.com/docs/performance/.

I noticed the performance is way lower on Firefox, I have read the docs and see the distinction between Firefox and Chrome, but, I'm wondering what I can do about this in terms of releasing this game to the web? Advise people to use Chrome?

The bad news is that Firefox definitely performs worse than chrome in a lot of cases. But here are my recommendations:

1. Profile the game in Firefox to see if you're hitting any specific code blocks (one example I know about is FF does not like recursive algorithms and really struggles with deep stack frames). If you can find a consistent hot path/slow call we may be able to work around it.
   
2. Try setting a fixed update, this will help with the shakiness and guarantee simulation stability with regards to physics/collisions. This effectively means that the draw and update are unhooked from each other, and multiple updates could run for a given draw. https://excaliburjs.com/docs/fixed-update/
3. Turn off collisions if you don't need them, or tune down the settings in realistic mode. You can also adjust the spatial partition bucket size.

   new ex.Engine({ physics: {enabled: false }}));

4. Turn off webgl and use 2D Canvas only, sometimes this can help on FF and depending the game might be okay. But if you use any custom shaders they wont work in this mode. https://excaliburjs.com/docs/graphics-context/#canvas-support

If you're willing to share some code with me (DM me on discord if you wish to keep it private). I can see if anything jumps out at me when it's running.