Managed to make it through Monday today. I entirely credit this to Rick Hunter, who singlehandedly elevates this game from "unplayable" to "not fun".
The one and only Postal Dude's voice's presence aside, there's really nothing positive I can say about this. You thought gunplay in P2 sucked? (Personally, I thought it was serviceable) Stay far away! Most of the weapons are recycled from 2, but they managed to make them feel worse. The shovel seems to have a reach of less than 10cm. Same goes for throwing matches. Fire looks way worse and doesn't seem to work anywhere as good as it did in 2 (When I accidentally set the Postal Dude on fire, running into NPCs didn't seem to have any effect on them at all). The world is much larger now, but there is not much interesting going on. The absolute worst so far are the missions: Much like the weapons, a lot of the missions are cookie-cutter rehashes of 2's missions. With one crucial difference: Missions in P2 were always to the point. And if a mission entailed annoying busywork (like standing in a long line), there was always the possibility to circumvent that by, you know, going postal. P4's Monday treats you to a boring-ass prison level that goes on forever and has nothing funny or interesting happening whatsoever. The big joke is that the warden tells you a wrong security code, resulting in a prison-wide riot, because he read the numbers upside down. If you reload the game and enter the "correct" code instead, it will produce the exact same outcome. You're then treated to a sewer mission that has you shovelling shit, changing lightbulbs and - joy of joys! the thing Postal fans were always craving! - a lengthy platforming section. I can remember exactly one platforming section in P2: a very brief bit in the Napalm Factory, which wouldn't take you more than roughly 30 seconds and comes across as a spot-on parody of scripted-to-hell, game-y level design conventions of games like Half-Life. P4's sewer level, on the other hand, goes on and on and on and on and on and on and on and on... And it's all so they can shoehorn in the obligatory Civvie-reference sewer count joke.
Just a side note, but I think it's worth mentioning, as it's the epitome of laziness: Most of the NPC chatter is recycled from Postal 2. I don't mean they had other voice actors redo the same lines - they straight-up copypasted P2's voice packs into this game. Playing the Early Access version, I figured that they were simply used as placeholders and that they would eventually be replaced with new dialogue. Unfortunately, that's not the case.
Maybe the following days will be better, but I doubt it. Even if everything worked as intended (which it doesn't - bugs abound, in one instance a level transition would spawn me
outside the level and then the game would do an autosave of me being hopelessly stuck in the netherworld for good measure), this thing would be pretty much unsalvageable. In order to make this fun, they would have to straight-up axe and/or redesign entire missions. In a way, this thing getting torn apart by the gaming journlolists is a badge of honor that the game doesn't merit. It simply sucks.
If anything, the review understates just how dull the experience actually is. The lolrandom "humor" in this game consists entirely of outdated references, stale memes and pee pee poo poo jokes that wouldn't get a giggle from a third-grader.
My recommendation: If you're a hardcore Postal fan, wait for a deep discount. Maybe by that time they will have fixed some of the more glaring issues (but I have doubts, since the most glaring issue is the gameplay itself - and the mission design in particular). As it is, this is more something for people who enjoy stuff like Goat Simulator.