I'm on Linux. I can see the following error in the log file:
ERROR: not found at " unlock_extra_hats! " in INTERPRET on line 91, stack:

The file it refers to is globals.df

A probable solution. I can now play the game. It might break later though...

1) remove the lines related to unlock_extra_hats
2) I got a new error related to mission-events.df, "fixed" by removing the following lines:

: mission-killed-multiplayer

// "TEAM COUNT: " team-count .. msg

// Is this even necessary?
team-leader #character .dead? if
TEAM_STATUS_DIED team-leader #character .decruit
then

// At least one char left
team-mission-count-permanent if then;

// Only reserve team remains
// team-stack-living depths nip if cyoa-car-fail then;
team-count-alive-permanent if cyoa-car-fail then;

// GAME OVER
clear-streak delete-the-game game-over
;