The two veteran actors did their best, provided decent acting performances and performed mostly all their action stunts on their own throughout the film. Just imagine ourselves at the age of 66 (Stallone) or 67 (Arnold) doing the same action stunts that they doing now...It's very impressive (not to mention they still manage to maintain well-trained ripped muscular bodies).
Action junkies or long-time Arnold/Stallone fans don't need to worry as the film is action-packed and fast-paced as well. I'm not fully sure whether there are plot holes or inconsistencies in the prison break plan (just watched the film once), but the plan should believable enough for the average movie viewers.
However, there are many unrealistic scenes throughout the film...There's too many shooting scenes where Ray and Emil managed to easily escape unscathed, despite all the guns shooting around in the scene. But in certain scenes, Ray managed to accurately fire his gun from a distance...Furthermore, the whole prison shouldn't explode when Ray (Stallone) shoots through the oil barrels with guns. Nowadays, people should well aware of the fact that explosions shouldn't have happened as oil barrels were just oils and a gun bullet would not able to trigger a considerable spark or gas to trigger a massive explosion. It is also not possible to unlock a door with a gunshot without getting hit by the bullet itself. For a maximum security prison, all the CCTV cameras should not be connected to a single network (opening up one single camera can switch off all the other cameras in the entire prison is a bit ridiculous).
Overall, despite all that, this is one of the relaxing, entertaining action film to watch just to reminiscent the good old days.
Note: The female CIA agent (Caitriona Balfe) look smoking hot and attractive in the film.