hooooooo boy. So this was a hearty 3 days.
A dreary amount of time dealing with how to rotate things around in a grid. Eventually I just accepted that the rotation math was "more realistic" than what I had original planned. "it's a feature!"
A late addition (as of about 3 hours ago) of adding pathing and mid-action collisions makes it far less ridiculous... but the real-time clock and delay makes it more annoying. And there's no time-dilation between the player's speed and the guard's chasing.
There's sort of a goal, obstacles, (the guards are surprisingly annoying), and jumping over stuff. Most important there's a pretty fleshed out system of grid-based turn-based inertia. Which was my main goal. So I'm calling this one a success.
Time is out. So the remaining bugs with collisions and the complete lack of deadly-falls between rooftops will just have to be ignored. All in all, for three days effort (6 if you count the last two attempts) I'm pretty happy with what I got.