It's ugly, it's badly executed, it's unfair. The story (?) is ridiculous. "Music" is repetitive and annoying. It is not hard in a good way, it's hard because its implementation is crap. Movement is crap. Targeting is crap, Enemy behavior is crap. Hitting somebody or getting hit is merely luck. you can shoot three times with a pump gun in a guy's face and he still kills you with bare hands. Enemies suddenly accelerate and are generally faster than you and see you from far beyond the screen. Well, I still played it a few chapters. Even behind what must be the worst boss fight in gaming history (prank caller). However then it got even worse. Indestructible SWAT guys and instant kills by invisible snipers are exactly the opposite of proper game design. At that point I already decided to stop playing, yet later decided to give it another try since everybody else can't be wrong. Just to learn that this crap excuse for a game let's you respawn right between two indestructible SWAT guys. Respawn -> Dead. Forever. No sorry, but everybody can be wrong. This would have been a bad game even by standards of the 80s and it's just a bad joke in the 21st century. Playing it is pure pain and why should I waste my precious time with self inflicted pain?
I like the graphic style. It's retro in the good way with some nice effects. Controls are subpar. E.g. you can't strafe or even move while shooting. Variety is small. While enemies are unique to each act, the enemy types don't really change. Level design is uninspired or boring. Most of the times it's just enemies and traps and you keep running back and forth to attack and evade enemy arrows/spells. Enemies run directly at you and get stuck at walls. Archers shoot at you even if they are wide outside your visible screen area. The only sort of tactics you can apply is to use the enemies' lousy pathfinding against them. Which feels more like a flaw than tactics. Worst of all is the design of the level boss fights. They respawn lower enemies like crazy and you will die a few times inevitably. In the end you stop trying to hide and just keep shooting and casting spells directly in front of the boss until you die and then you repeat that until he dies. There are no weak spots, there is no strategy, it's just dumb. And when you defeated the final boss and just missed on single hidden plank in the 12 floors, the game hits you in the face and lets you die without allowing you to escape the castle. There are some riddles which are all trial and error, usually bombing you to nirvana if you guessed the wrong order of four switches to activate. And there are some secret areas which are usually entered by shooting at walls or running trough walls. This implies a lot of running around and shooting at walls. Which is quite annoying. There are manual save points and autosave on death. You can't manage your save games in any way (only on operating system level). So chances are you end up at the boss fight with no life left and as the boss fights need several lives due to the lack of any sensible strategy, you are screwed and have to play through the whole game again. This is just treating player's time and interest with scorn.
It might be unfair to give a bad rating to complain about the treatment of customers, but so be it. I hate how small indie games follow the bad example of Bioware/EA and the likes. Sell me one game, don't break it into chunk and don't try to sell me the same game again and again as Gold, GotY, Platinum or whatever edition. The PIT serves as cautionary tale of how not to do it. This DLC here and that DLC there but you need to upgrade to Gold and need the other DLC to use it. To make things worse, when GOG realized they made a mistake when adding Juggernaut to some/all accounts of customers who already bought PIT once or twice ("Gold"), their reaction was the worst possible: they just deleted it again. This is completely legal obviously, but taking away games from a user's account is just the single unforgivable thing that should never ever happen. It's really saddening to see an attitude unfold here that we tried to avoid by supporting GOG in the first place.