The tutorial asks me to type anything in the console and I type 'anything' and get an error of course.  Then it asks me to spawn a creep and I copy the code hint:

Game.spawns.Spawn1.createCreep( [WORK, CARRY, MOVE], 'Worker1' );

Which works and says 'Worker1' in the console.  Looking in the 'Memory' tab I see Worker1 {0} under the creeps, however nothing happens.  I don't see the creep in the game window and the tutorial won't continue.  I upped the speed to 500% and waited a long time and still nothing.  The only error I see in the console is:

GET https://screeps.com/a/vendor/jsoneditor/dist/img/jsoneditor-icons.png 404 (Not Found)

There's also a warning that was there before I created my worker:

SVG's SMIL animations (<animate>, <set>, etc.) are deprecated and will be removed. Please use CSS animations or Web animations instead.

I tried creating a few more (Worker2..5) and got -6 as the result instead of a creep.  Then I called Game.spawns.Spawn1.canCreateCreep([WORK,CARRY,MOVE]) and it returned -6 as well.