It is an interesting study in how to combine a movable breechblock design with a traditional hammer back action lock.
It reminds me of the very early Alexander Henry falling block rifles which literally had a bar action lock let into the side of the modern (in the day) falling block action.
Taken individually, each mechanism is quite simple.
The lever and tilting or falling block operates just the block and the extractor and houses the firing pin.
The lock/trigger arrangement performs the duty of striking the hammer upon the firing pin and can incorporate a set trigger as in this gun.
Very cool for sure.