From 1:30 the Su-26 is hanging by the prop:
The Su-26 is a crazy plane, and even though it looks a bit wrong in the original poster's vid I think that when you reach these extremes of flight any sim is struggling to completely faithfully model the reality of flight "at the edge of the envelope". It would take a Cray supercomputer (probably churning through data for a night and not rendering in real-time) to totally correctly model the ultra-chaotic Mandelbrot world of aerodynamics...