Game crashed after a sarcastic "theres no solution, we will inform you blabla.." window to desktop.
And i´m even at the beginning of the game (kill mission at lvl2) even after speedrun-finishing it, it wont save that i made it.
The only solution i recommend to avoid the acs.exe crash, dont buy syndicate till there´s just a try this or that solving.

Even after months they where not able to fix it so it stays in a kind of beta state for me (like every game that need patches after so called "final")

And for the for the fanboys and/or payed ones: No - in 99,99% its not the systems fault as you can read in tons of crash complains.