The only problem I had with Hackmaster is the fact that the comedy is a little over the top and too many people take it to the extreme, acting like they do in the comics e.g. killing random NPCs just because they're NPCs, ignoring all roleplaying and just trying to kill things, etc. There's also the "GM vs. Players" mentality, which because its a staple of the comics makes people think that's how the game is supposed to be played, instead of a tongue-in-cheek attempt to poke fun at early D&D.
The first and only time I played Hackmaster, which was several years ago at a now defunct game store, the group did just this and would actually get new players, give them a minor magic item, and then kill them later on for it, or screwing with players just because (the shop owner's son had the most powerful character and forced everyone else to be his servants on pain of death, basically). I actually causes quite a scandal on the old Hackmaster forums by talking about it... this was in the day of the Hackmaster Retailer Association, and it actually resulted in the game store being kicked out, because KenzerCo investigated it or some such. Some of the disgruntled players (the ones who had suffered some of this nonsense, no less!) then came onto the forums to flame and make death threats at me.
Fun times.