This is not the game you play for an epic, sweeping narrative, multiple dialogue choices, or cringe-worthy NPC romances; no, this game is your one and only stop for mountains of loot, nearly-endless character build options, and fast-clicking, monster-exploding ARPG fun. Personally, the main attraction for me has been the freedom you have in constructing your classes' skills/spells. The sheer number of possible class and skill combinations is already overwhelming, but then you factor in a literal galaxy of constellations - each with their own branching skill trees separate from your classes - and skills granted by items and item augments, and you may end up light-headed trying to conceptualize how many different ways you can take your character. Other than that, it looks good, runs well, and is very stable.
Even in its time Kingpin was a mediocre mess of a game running on the aging Quake engine, but it had a gimmick in limb dismemberment which set it apart, not to mention being practically unheard of in a 3D game in 1999 (Soldier of Fortune two years later would up the ante for gore in a shooter.) Other than that, it was a wholly forgettable game.