Despite not having anything like the coding or physics skills required, I've always dreamed of making a space adventure game like Frontier: Elite 2. The Space Adventure Simulator was a way to explore what you could do with randomly generated storylines while sidestepping the need to be any good at programming, and it was a lot of fun to make despite its many flaws.
My biggest mistake in making it was not sticking to my original plan more closely and letting the whole thing get too complicated. The original idea was to present a situation or story premise to which the player would respond by 'staking' a number of crew members to send on the away mission. The whole thing would be completely random in that any situation could go in a positive or negative direction with lots of variations so it didn't get repetitive too quickly.
As it was so easy to code I thought I'd be clever and start adding a kind of resource management idea that I hadn't thought through properly, and then the alien races and battle systems, all in an attempt to create my own text version of Frontier. All these extra elements meant that the original idea of betting on outcomes with crew members as the currency became watered down and I never felt that it worked properly as a game.
The original idea would have recorded each 'level' of the story as a chapter in the Captains log and this would create a unique story arch each time you played a game. I've since developed this idea a bit further, with a few twists, to use as the basis for TSAS3, but I have to finish TSAS2 first, where I'm more concerned with creating the locations and the galaxy itself and working out how to make large, randomly generated worlds using the smallest amount of memory I can get away with.
I will just add, the biggest flaw of all in this game is that it requires you to play it long enough to die a few times to get the main story going properly. If you get lucky with where you begin and make allies quickly you can survive easily enough and unlock a few easter eggs but you won't get to attempt the specific set of objectives needed to complete the game properly!