Revas is an extreme example during the first boss. She is a pretty challenging opponent if you challenge her to a normal knife fight (she has boss-level health, does double damage, always instantly counterattacks after a block, and has a unique moveset including a 3 hit combo that can take off 1 health bar with each hit). However, you can just maul her to death with the Ulaks, as it takes about 7 hits to beat her, and if you just keep stabbing her, she won't even be able to attack.
Compared to the two consecutive Alpha Drones leading up to the fight, Spinner in his Powered Armor isn't anything special. He's got a boatload of HP and a machine gun that can chew through your health in no time, but all Alpha Drones come with the latter and a rocket launcher, and they have to be taken down in a specific way, while Riddick can either just pop out and keep plugging Spinner with explosive SCAR projectiles, or just chuck an Alpha Drone grenade at him.
Revas in the Final Boss fight can be very anticlimactic, as she's a Puzzle Boss that can be taken out in just a few seconds if you know what you're supposed to do. A shame because with her unique power armor and moveset and the layout of the room you fight her in (with lots of destructible cover) she could have made a decent boss fight as a straightforward shootout opponent.
Catharsis Factor: Jaylor is a completely unrepentant and depraved scumbag, locked up because he's too evil even for the Dark Athena's crew. So when he murders Ellen and then hides while demanding that Riddick put his weapons away and "fight like a man", there's nothing stopping the player from holstering their gun, waiting for him to come out to fistfight them, and then just pulling the gun back out and putting him down in a few seconds.
Complete Monster: Captain Gale Revas is the commander of the pirate/mercenary ship the Dark Athena. When she joined the crew she seduced the original Captain, then had him overthrown and thrown in a cell so she could have the ship refitted to attack unsuspecting vessels and settler worlds. The planetary assaults are full of Rape, Pillage, and Burn, with unarmed civilians being indiscriminately killed and tossed in sewers, the settlements wiped out, and the survivors either sold as slaves or harvested into mindless remote-controlled cyborgs. The rest of the crew is kept in line with threats of forced cyborg conversion (the "Drone Mile") or trips to "The Dentist". When Revas discovers Lynn Silverman, the little girl who stowed away on her ship after Revas enslaved her mother and harvested her father, she tries to murder Lynn.
Demonic Spiders: Appropriately enough, the Spider Drones, who can whittle down all of your health in a matter of seconds, and cannot be killed unless hit SPOT ON. They resemble the peaceful little alien creatures you encounter in the vents, so they seem harmless at first, until said drones pumps you full of unending machine gun rounds. Accentuated by the fact they are often placed with one on either side, so the player can't even take cover from them, it takes about 1 second to take out 2 whole health blocks, and that even beats a mech weapon, which deals about half that. Fortunately, you have the One-Hit Kill SCAR Gun at this point, and they can be easily spotted from a distance, even when they're hidden behind cover, once you know how to spot them from far away, and that a Laser Sight at this point in the game always hints at a Spider Drone lying in wait somewhere.
Tranquilizer gun, which stuns an enemy. It is effective against high-health humans that would otherwise soak a large number of bullets. It would be much less gamebreaking, if it weren't for the high recovery time (about 8 seconds), and that it leaves them open to an almost instant OHKO.
The SCAR Gun in the second half. It fires one shot at a time and has a long recharge, but since the ammo are remotely detonated charges, they can kill any Merc or Drone they stick on, or that is just close to them. You'll rarely use anything else after you get it, also because, given it's necessary to solve some puzzles and bosses, it has unlimited ammo.
Jerkass Woobie: Revas has the potential to be this because of her Dark and Troubled Past where she lived a life of poverty growing up poor in the slums. Unfortunately, the "Woobie" part is averted by her capturing innocent people and turning them into drones.
