5/5 Sub-4 Will Take Your Breath Away!
  by Matthew S. Haglund (Duluth, MN USA)
Wow. First off, I just want to say that this movie is truly a significant achievement in the history of filmmaking. Treat Williams stars in this thrilling drama, that sends a humble mercenary into the very heart of a Neo-Nazi conspiracy. Set in the late 1990's, our mercenary-hero (armed with high-explosives and a Ph.D. in modern literature) becomes a substitute at a military academy, only to discover it's been overrun by Nazi-thugs and a world-class exterminator. Peppered with megabuck special effects, including a scene in which the intolerant Nazis blow up a minority owned power plant, this movie proves itself to be a treat (no pun intended) for the eyes, as well as the soul. You'll truly feel like you're part of the action as Treat crushes his students with a bulldozer, beats ass in the classroom with chalkboard erasers, and kills the Nazi-principal as he screams in desperation for "racial purity". Put the children to bed for this one! "Substitute 4: Failure Is not an Option" will affect you in ways few films have. Its realistic portrayal of Nazism in our military academies is a silent and chilling reminder of who's really in charge of our children's futures. Your life will never be the same, once you see this film. Its title may seem cryptic, yet its message rings clear. Failure is NOT an Option!

2/5 Well, it's no "Substitute 3"
  by John Markley (Oak Lawn, IL USA)
Part four in what is arguably this decade's finest educator-themed action franchise. Treat Williams goes undercover in a Nazi military academy to root out the evil plot that lies within, battling an evil school commandant, brainwashed Nazi students, and a Korean guy whose presence is never adequately explained. You'd think a movie willing to go with a premise that ludicrous would have to be entertaining, but most of it is pretty dull. The movie tends to drag- there's far too many talky scenes about how much the evil white supremacist commandant (palyed by a sort of poor man's John Malkovich) hates atheistic multicultural liberals and not nearly enough action. The ratio of liberal sermonizing to buttkicking is badly miscalculated.
It gets two stars instead of one for a couple of good action sequences (I especially liked the death by bulldozer) and the presence of Treat Williams, who's much too good for this sort of thing. Overall, though, I wouldn't bother unless it's the only thing on cable- there's much more entertaining action fare out there.

4/5 Not too bad (as far as sequels go)
  by Scott Wilson (Ohio)
As a big fan of The Substitute series (which explains the four stars), I didn't think it was that bad. Treat Williams gives his third performance as Karl Thomasson, and in this film he goes undercover(as usual) in a military academy to infiltrate a Neo-Nazi group. Lots of action, hand-to-hand combat (only to be expected from the Sub), and Angie Everhart provides some pleasing eye candy. If you're not too big on The Sub, this might not be the movie for you. If you are, it ain't that bad.

4/5 Treat Yourself
  by Stanley Runk (Camp North Pines)
Treat Williams is back, still kicking [...] and asking questions later. At this pooint I think most people now identify Williams as The Substitute considering this is his third outing as the mercenary with a heart of gold. Once again he's lured into a deadly mission by an old war pal. He seems to be a sucker for taking on these missions as charity cases coz he never gets paid. Naturally the gig has him as a history teacher at a military academy. He discovers a secret group within the school called the "werewolves". The Werewolves are an angry white supremacist bunch who are in training for a civil war between black and white they believe is happening soon. They like to run around and destroy property owned and supported by minorities. The leader of the group(The always scary Patrick Kilpatrick) is also the commendant of the academy. Big shocker there, huh? Williams goes about his routine of wooing the leading lady, beating up at least one kid in the classroom(with chalkboard erasers!), being all round sneaky and saving the day with a little help from his friends. His mission is to get his buddy's(the guy who sent him on this mission) nephew out of the Werewolves. Being that this is a part 4 in a series it can't help but feel a little stale, but it deals with some scary subject matter(neo-nazis) and that makes it pretty solid and pretty interesting. You'll like it if you like the others. Personally I hope Williams does at least one more of these films.

3/5 Watchable, but not the best installment of the series
  by Steve Miles (Winston-Salem, NC)
While it's not a bad movie, The Substitute 4 is the worst of the 4 Substitute movies. One of the main reasons is the film quality. The first 3 movies seemed to have better "look" to them and seemed like they could have been shown in a theater. This one looks more like a straight to video release. Some parts of the movie are slow, but it still has enough action to keep you interested.

Treat Williams is good as usual. Angie Everhart is OK - but I don't know why she was there, and some of the bad guys are pretty bad actors. The fight scenes are ok - even if they are a little predictable. A "special effect" explosion at a dam is pretty funny looking. There's some decent nudity, the classroom fight scene is funny, and a kid falling on some spike at the dam was cool too. The final battle with the bad guy was cheesy - and like the other reviewer said - why would a racist have a asian henchman?! The twist with Everhart is a little unexplainable as well.