I have developed a 2D space trading game, yet in the final stage of the development of the game engine, I am struggling to find the optimal size of my planetary system(s) and the maximum velocity of my spaceship. Setting the correct dimensions is crucial for the further development of the project, as it lays the foundation for many elements, technology and story line. I encountered a few shortcomings during the worldbuilding stage and I would appreciate any help with it.
How can I creatively reason to a player an imposed speed limit of his or her spaceship, given that in reality with constant acceleration a spaceship is only limited by the speed of light? I chose to limit the maximum velocity of a vessel, as it otherwise becomes (technically) impractical to engage with other spaceship in a (dogfight) combat.
Ultimately related to speed, how can I determine the ideal size of an average planetary system (i.e. usually one star and planets in orbits), the number of planets and the time it could take on average to travel from a planet in the outer orbit to a planet closer to the sun, both in game time and real time? Ideally I would like the game to feel realistic and exciting to get across the planetary system, yet not feel too boring with longer periods of nothing happening. Currently I have set 1 (real) minute minute to be 1 (game) hour; what is a reasonably good conversion ratio?
I would like the trade to be challenging. However, if people can simply see the prevailing prices on each planet beforehand, there is not much challenge for finding the optimal trade. I can cut the communication but then how can I reason to a player that they can only see the prevailing prices of goods when they visit a planet, however, not when flying in space? Is there any other way to make trade more challenging and reason it to the player?
Notes: (1) Players control a ship or even a fleet of ships using mostly their mouse, something similar to that that (early demo of my game). (2) There will be asteroids to visit that can be mined etc. (3) I want to include around 200 AI players per planetary system, but can technically go up to as many as 2000.
Edit: To narrow the scope down, I though I will provide a little bit more info on the game so far--what it can do, what it can't and what I can implement.
A key element of the game is that it contains an entirely simulated real-time economy with prices that are determined by supply and demand through AI generated traders and human players. There is a plan to include a interplanetary stock market, derivatives, commodities and the possibility to mine asteroids and build factories on planets that transform commodities in more complex products.
In terms of propulsion technology, there will be two essential methods to get across. The first is within a planetary system by means of normal propulsion such as nuclear fusion, solar sails, anti-matter, impulse etc. This will be used for interplanetary exploration, trade and sometimes fights. There will be RPG/Adventure elements such as exploring ancient civilizations, galactic phenomena, nebulas etc.
The other propulsion technology is enabling interstellar flight. The current working idea is that ships can enter a higher dimensional plane by creating a temporary rift in space. A ship then enters into a (nearly) higher spatial dimension where it is possible to travel light years in a relatively short time (e.g. days). As mentioned, this technology is independent from the first interplanetary propulsion and it only works when there are no major gravitational disturbances around the ship such as planets, asteroids or other ships. So you need to be flying a bit out of the planetary system to activate it and therefore it won't be possible to escape from a fight or as long there are objects around at a certain radius.
Other ship technologies include different type of energy generators, shields, weapons, probes, radars, scanners. The ship is capable to have a fight, but not just dumb-down clicking around and about. With the correct speed it should rather feel tactical despite being in real time. It may take a minute to take another ship down, and therefore fights are not be overly frequent but if one wishes to engage in more fight than rpg/trade, that's up to them. As there will be RPG elements, gaining experience will increase maneuverability, aim accuracy etc., to make fights even more interesting.
With regards to the story line. The current working version envisages that earth experienced an attack from an unknown force and while being transported out from the solar system with a small vessel (as slave/prisoner), there was an unknown energy burst on the vessel and you find yourself in a different star system with all but you dead. You manage to get out of your cell and learn to take control of the severely damaged ship and get to what looks like a space station. While this seems not to original, what people will realize during the game, that your ship not only had been transported hundreds of light years away, but also around 7 years back in time. So, in a time frame of seven years, you can explore the reasons behind this attack and prevent it from happening by means of either becoming very powerful individual (trade+diplomacy) or tactical combat (up to controlling a fleet to fight against the invading force).