Certainly, this isn't sufficient to even induce a smirk, and is just outright bad. Most of the humor in Postal 4 would still feel comfortable in Postal 2, a video game that came out in 2002, and it wouldn't have actually been amusing then either. Even the most recent popular culture references in the game are still relatively dated, with nods to the similarity Breaking Bad, Jailed Development, and Twin Peaks.
Why Peter Dinklage, you might be asking? Probably due to the fact that it's easy to alter his name to "Tinklage." That, and the reality that the series has a precedent for making enjoyable of little people. Rather surprisingly, the voice performing is relatively decent for the most part, specifically thinking about the material the cast needs to work with.
The only things it has in spades are continuous technical issues that just compound the video game's lengthy checklist of egregious imperfections. Running With Scissors might consider this review a badge of honor, thinking about that the game being bad is relatively part of the gag, however don't for a second think that Postal 4 even touches the world of "So bad, it's great." There's absolutely nothing redeemable about this video game.
Maybe I'm supposed to dislike Postal 4: No Regerts. Possibly that's sort of the point. This Is Noteworthy Keeping up Scissors explains it as a sequel to "the worst video game ever," Postal 2, renowned for its indecency and rough edges. If the goal was to make one that's even worse then that's certainly been attained, but that gag does not indicate it's ever enjoyable to actually play.
Whether you're in on the joke or not, there's nothing available here other than pain. Postal 4 bills itself as a satirical open-world shooter that wants to push the limitations with a vulgar, over-the-top design and a crass subject in the vein of South Park. The main distinction is that South Park usually supports its outrageous ideas with smart writing and some sort of coherent message or implying behind the madness, while Postal 4 almost never sticks the landing.