When i played STO the first time a still was REALLY exitet. The Tutorial was nice, the Azura mission was still intresting.... and after that the game startet to get repetetive and boring. After that it startet that one mission looked like the other.
So they dont want to let the Demo players see how boring that game is later and just show the part that appears intresting at first i guess.
This Demo is way to short to determine if you like this game or not. You cant even play it with your friends, because their only goning through the tutorial and that very first mission (SS Azura?).
If've handed my key to two buddys. One liked the game, but was unsure when we couldn't play more than one mission together. He bought STO as he discovered you can get it for 20-30€, but that still leaves a bit of a bad conscience to me.
The other one - hes a trekkie - didnt liked the tutorial and the the graphics (e.g. those really giant rooms, which he found had nothing to do with ST) and then was really upset as the demo ended that quickliy (i think he has downloaded it for nearly a day) and don't want to play STO again. If the Demo had been a bit longer I think he could have spotted some parts of the game that he had liked. Maybe not enough to buy and play the game, but enough to not being totally upset with it and never looking at it again.