A real-time speedrun should just play with full time acceleration on at all time,s but I think "fewest days" is interesting, since it's funny to fight Ploxis BEFORE he ever tries to parley with you - The main difference is that you have to be much more careful managing fuel throughout almost the entire game and be sure to follow your trail of homeworlds to "top off" -

Right now I'm looking at -this - but their is a ton of fat to cut out - I didn't understand the Eltanin fully, I visited the Exquivan before AND after being told to, etc - I believe a shortest IGT run could get in the 220-230 range, and I think it would be very impressive.

Day 19 : 9 Alliance Members met Day 26 : Arilou message about Orz recevied Day 28 : Picus event Day 79 : Eltanin event (in the current belief that it is manually triggered) Day 92 : Spathi defect Day 107 : Xchagger sidequest finished Day 118 : Ultron fixed Day 169 : Arilou message to start Equivan sidequest Day 179 : Tyche event Day 192 : Syreen distress call for Equivan sidequest Day 197 : Equivan Find Precursor Vessel Day 210 : Lk Stuff Done Day 213 : Owa homeworld visited and Clair allied Day 221 : All rainbow worlds visited Day 229 : K'tang allied, Ploxis ships collected, Chmrr revived. Day 241 : Fight Plexor Day 246 : Fight Orz Day 249 : Find Plexor peace meeting Day 256 : Fight Herald Day 259 : Plexor Forcibly sends you into the peace meeting despite already being dead Day 263 : We win the game.