The main hallway changes from a round shape to a coffin shape late in the film as the crew experiences the multiverse.
Sean Maher did all his own stunts.
The rings on the ship change color throughout the film as the characters pass through the different time periods.
For some, the movie can be confusing, to show repetitive action but over periods of time, the interior of the ship construction and equipment layout is replaced, reworked or rearranged to give the viewer a sense of disorder and time warp.
The scene in the bunk room with multiple overlays of Dr Anderson (Sean Maher) was shot using an automotive type manufacturing robot, programmed for repetitive moves to capture the actor's movement while the actor moved but fixed relative to the camera movements. This resulted in an unbelievable end effect with out any major editing. This method was used several other place. See if you can find them.