Someone who had managed to convert games to Unity before described the task that lay ahead of us as follows. Imagine that there's a rave going on in an abandoned railroad car— people laughing, dancing, letting loose. Now, the ravers—they're the players of your game, and you need to replace the car without anybody noticing so the party doesn't have to stop.
This is essentially what we were faced with. Support for Flash was almost at an end, which meant we had to convert Clockmaker into a Unity game. At that point, it was nine years old, so you can imagine the sheer amount of legacy code. Amazingly, we ensured the smooth transition without anything breaking. And this is how we did it.