If the game/computer lags a bit when you open up a planet in just the right position and perhaps you click a bit fast - you risk cancelling the constructions of ships by accident and losing all associated progress. This may be especially painful if what you just stopped was the construction a Colony-ship or something really expensive.



I would therefore suggest the following:

• Save progress for items currently not on the top of the queue - this will simplify and allow partial constructions to be put outside the queue and not below your default "conversion-order"
• Display per-item progress.
  
  

If not, then at least add a confirmation dialogue when cancelling an item which has had some progress.



I'm also somewhat surprised by the lack of a conditional modifier for items such as the Colony-ship. A system with 100 food and 50 construction power will construct a colony ship just as fast as a system with 1 food and 50 construction power. This is in some ways okay.



However, what I find strange is the fact that both are affected in the same way - the 100 food produced simply vanish completely instead of having a conditional modifier (-100% until you have 40 food - perhaps - and then it is -40 instead) or having an additional clause stating that X amount of the construction progress on a Colony-ship can be made using food.