Sounds like documentation issue, with the thought being that the supplied list of objects is already filtered.

On the topic of filtering, is the server-side component capable of array comprehension? Like so:

  »Game.creeps[Object.keys(Game.creeps)[0]].pos.findClosest([Game.creeps[Object.keys(Game.creeps)[0]]], {filter: function(e) {console.log('hai'); return false;}});
  « [creep Eva]
  »Game.creeps[Object.keys(Game.creeps)[0]].pos.findClosest([for (creep of Object.keys(Game.creeps)) if (creep !== Object.keys(Game.creeps)[0]) Game.creeps[creep]], {filter: function(e) {console.log('hai'); return false;}});
  «[creep Julia]

Never ran into the need for this myself. Is it a big issue on the server-side version?

I take it your investigation included completely removing the problematic bit of code from execution?
Try comparing to undefined instead, like so:

for (var name in Memory.creeps) {
    if (Game.creeps[name] === undefined) {
        delete Memory.creeps[name];
    }
}

Reported upstream several times already.
There's a patch in the work here:

Support variable-width text

But seems like things are stuck on the handling of wrapped text.

Set up a tasklist in memory and check to make sure you have enough CPU time left before running each task. You can store an historical average of all tasks time usage as a point of reference.

I do wonder, is Memory writes immediate? If so you could use that to see sort of where it terminates.

I think console.log writes to stdout by default so at least that ought to be accessible, or is sandboxing or somesuch hindering this?

Sounds like that's the plan:

Also, soon after the release, we're going to publish the game engine as a standalone node.js package in order for you to be able to launch the game simulation completely locally and thus test your own scripts.

Breaking change: Exit objects removed from the game. Now all non-wall border squares (i.e. with x or y equal to 0 or 49) are treated as exits.

It's around alpha status, so I wouldn't expect anything to stay stable.

The private Early Preview stage starts on May 20.

Breaking changes are noted in the changelogs, so keeping tabs on those are a good idea.

In addition to getUsedCpu, the update before that removed Exit, removed some deprecated functions, and the constants on the Game object.

You may be able to do: Memory.roles.foo[0] = function(){}.toSource()

Curious though, why do you want to do that? It takes more space and doesn't really convey any real info.

Be sure to use strict mode by adding "use strict" at the top of your files.

Also, see this answer to another question. Particularly this bit:

Also, soon after the release, we're going to publish the game engine as a standalone node.js package in order for you to be able to launch the game simulation completely locally and thus test your own scripts.

What does your main look like? At least the bit that calls these functions.

I think it were mentioned that the last moveTo specified is the one that affects the creep, so it sounds like the way you're matching towers is set up wrong somehow.