Security Hell Angels appear only in the Prison, and look like the closest thing to guards in the level. They wear grey armor with a pendant that has a symbol of peace on it, and they have silver helmets on their heads. They attack with tasers that can do decent damage if cornered. Combined with the Hell Bikers, they can prove to be a major hindrance. Despite this, they are probably the weakest of the 3 Hell Angel classes, as they can only use a melee attack. They also appear in Highway to Hell.
Punk Hell Angels appear in the City on Water and also in Riot. They wear a red, shirtless jacket, with an orange, glowing pentagram-pendant (which dims after they've been gibbed), skull knee pads, and have a brownish helmet on their heads. They attack by beating you with clubs. They appear in giant swarms as well, so be careful. If you distance yourself from them, they throw Molotov cocktails at you, which can rack up damage fast. In comparison to Security version they are more dangerous.
Leader Hell Angels are the last version to appear and they show up in the Docks. They look similar to Punks, but wear grey shirtless jacket, have pedant that has symbol of peace and they have reddish helmets on their heads. This version uses rocket launchers on you. Despite this, their rockets are easy to dodge, and its easy to get them caught up in crossfire. If you bunnyhop around them and lead their shots on their pals. However, they are still the strongest version of the Hell Angels to appear in the game. They also have an interesting attack - They use their rockets to "rocket jump", by firing the rocket at their feet, sending them flying into the air. They usually follow up with a second rocket aimed at you while flying in the air.
The Punks may represent gangs, as they use crude weapons, wear punk-ish clothes, and even have Mohawks on their head.
The Security version may represent corruption in law enforcement. They even seem to run in stride compared to the Punks, who simply tear their way to you.
The Leader represents the power of being a leader.
The leaders have rather hilarious running animations.
The HellAngel's texture is made by a company called "Vyoor" dating back in 2002, being one of the oldest known enemy. The company name and date can be found on the texture of every single HellAngel, for the Punk and Dock version there is also a red text attached to it "& JUST WAS HERE"