That spike really is nice to see.

This also apprears to happen in mission 2 if you perform the same action on the burner inserter you as asked to inspect at the start of that mission.

If during the first tutorial mission you put fuel in out of habit using something like ctrl+left click results in a scripting error and a crash to main menu. Error text: Notice Error 2 while running the event handler: ...Data\Roaming\Factorio\temp\currentlyplayingc|control.lua:370: attempt to index ...

One of the iron nodes in the first mission has 0 iron in it. This allows you to mine it into negative numbers and (presumably) would allow you to mine it forever:

http://imgur.com/ASbBY7p