I see messages like

[2:04:56] Unit deathChecker: Found dead creep guard tibuma. Deleting...
[2:04:56] Unit deathChecker: Found dead creep transporter beyurayoke. Copying..

which are not a part of my code output. I guess it's logs of other players

It's not a session based game. So it should have long term goals.
Each source gives 10energy/tick, using of 3 sources in the room gives 30energy/tick.
If tick==second then player can get 30x86400 = 2.6 millions per day. So you can capture second room on second day.
It's fast enough for MMO imo.

Commiting scripts using direct API access

Commiting local scripts using Grunt

room.find doesn't know creep position so it can't return closest. It returns array of all object of specified type.

If you want closest hostile creep, then use

creep.pos.findClosest(FIND_HOSTILE_CREEPS)

You can also filter hostile creeps to exclude source keepers. Something like

room.find(FIND_HOSTILE_CREEPS, {
    filter:function(enemy){enemy.owner.username !== 'Source Keeper'}
})

Artem from Screeps, thanks for answers.

"There is no fog of war."
programmatically you can have access to the rooms with your creeps/structures only.
Screeps is about code, so actually there is a fog of war for my creeps.
It's a bit disappointing. It gives advantages to players with higher online, just because they can see information which AI can't.
Any chance you'll make same info available to humans and AI?

"No, it will not be active if you don't have any game objects, since it simply doesn't make any sense."
It was a part of idea to start new game by code. It can analyze rooms, find best spot and create a spawn there. But I agree it makes no sense without ability to access room data without creep/structure and place spawn.

World mode will be launched soon. So I have couple questions about world mode behavior and how it works together with survival mode.
1. Are CPU ticks shared between modes?
2. Will code (main module) called once per tick or once per mode per tick?
3. Will Game.creeps contain all my creeps in all modes or just in "current mode"?
4. Can I see hostile creeps and/or terrain data in other rooms without having of my creeps there? Manually or via room object.
5. What error will be returned if I'll try to place construction site without owning a room controller?
6. Are my buildings continue to function as intended if I lose room controller?
7. Which rooms will be in Game.rooms object ("available to you")? Where I have spanwer/building/creeps, whole world, etc.
8 Can I place first spawn by code?
9 Will be code executed every tick if I lost everything?
10 "To capture each new Controller, you must have a corresponding Global Control Level which is displayed in your profile" Does it mean that I need GCL 10 to control 10 rooms?
11 "our room will be blocked by walls defending from outside attacks for 3 days" Can I detect if room is blocked temporarily or it has no this exit? Can I get time left to my room unblocking?
P.S I don't know what is the better way, either separate post for each question or the way I did it.