I think engines and batterys need to be better defined.
how do each work?
why is it that although it apears that the ships have only should have the ability to move forward?

I think that turbo should be more of a long term boost, which increases you speed for a duration of time that degrades so you dont need to constantly press the button. the speed and how long each boost would lastand cost engergy wise would be determined by the battery and the engine used.

later on I think planets should be added in perhaps, and larger ships, which can do things that smaller ships cant, like carry large amounts of cargo and travel larger distances. perhaps they also would be able to use wurmholes which travel farther than those used by small ships and could ferrie smaller ships for a fee to systems to far to travel to by normal means.

Yea, it doesn't make much sense that when you release the turbo key, you STOP...

BAlance issues.

panic, it makes absolutely no sense at all, except that it makes the game fun. Max speed is completely artificial, and very important to the enjoyability of the game.

Necro, larger ships will be introduced to the game as part of an upgrade after the game is released, but due to money/time issues they won't appear in the version released this summer. As for planets it's extremely unlike due to the massive difference in scale.