Esteemed colleague,
Your feedback is much appreciated. Here are my opinions on your points:
I. Schemaverse is not an mmo and the AI programming part is considered a secondary not the primary way to play.
II. You should use the spawning property to avoid processing of creeps which are not yet alive. Every other creep in your Game.creeps array should be treated the same (imho).
III. You should definitely, without a doubt use an external editor. I strongly suggest webstorm if you are looking for an IDE which takes care of minor details for you or sublime if you prefer to keep things light. This allows you to use a proper git structure for managing your code. If you must use the editor for whatever reason, then accept the various inadequacies it might have. Eg, writing/saving code whilst looking at the world map will be lost once you zoom into a room.
IV. Regarding testing your battle code or more difficult scenarios. Simulator is one way which works, although I haven't used it much. The alternative is to just send out units to neighbors or source keepers to test things out.
As a closing note, you should realize that this game is slow. Really, really slow. If you make a mistake and lose a few ticks while understanding what is happening, it will not have a true impact.
For my first 7 days, I think an aggregate of 3 days was lost due to script errors.
Kind regards,Atavus
PS: I've been playing video games since 1990 and I can tell you this one is a pretty unique experience. It may draw inspiration from a lot of other games, but after devouring thousands of games, I can say it is quite an original experience.