One out of three ain't good
The stealth sections remain impressive because of the simple implementation. Open areas with boxes, many shadows and patrolling drones are the perfect playground. Riddick can move between the shadows, over boxes or just come up behind enemies to instantly kill them. Drones wander slowly around allowing you to take them out however you want. The easiest way is to just walk up behind them and stab them in the side of the head. The reason the stealth works well is probably linked to being able to hear heartbeats. There won't be any surprises when moving around a corner because you will know where these drones are.
Unfortunately there is very little depth in the stealth areas. You can drop from above Drones for an instant kill, which may not eve work. Alternatively you can grab a dead drone and use its weapon on another. Unlike the Thief games you cannot attack at range silently, nor can you remove light sources. You can't do much distracting unless you leave a body exposed on purpose. What makes things worse is the stealth AI seems to have two states, oblivious and hunter.
There is no in between fuzzy state you see in other stealth games. No point where the drones might be wondering what that object was moving in the shadow and casually investigate. They either see you or they don't and this makes for gameplay that deteriorates into action if they see you since they run and open fire alerting nearby drones. You can just pick up a dead drone and shoot a few guys and move to the next drone. In between the stealth and shooting sections are the lacklustre hand to hand combat battles.
The game spreads these brawls out and will even toss in some tougher fisticuffs just to make the brawling even sillier. Standard enemies can be beaten with simple block / counter attacks but you can also move back and attack quickly after they miss. Against boss brawlers the block / counter tactic becomes a series of dozens of counters and blocks with little result, thanks to their illogical high health. The instant counter for bosses is extremely unnatural and makes the fist combat frustrating.
In the case of a boss brawler, Iron Lord, you can just cheat the AI by running up to him in the "battle cry" state and quickly slash Ulaks in his face before he can even attack. If you try to run around him to get to a vent the game warps Mr Lord to your position not allowing you to progress, so much for stealth. There was one boss brawler who wanted fist combat if I lowered my weapons. A few ludicrous counters later and I just used my gun to kill him. A later boss brawl fight even has your gun kicked away in a cutscene, leaving you with no guns even though you had four previously. Not that you will want guns; the shooting elements in Riddick are close to the bottom of the genre.
The final aspect of Dark Athena, and by far the worst, is the shooting. The weapons feel poor with bullets that spread ridiculously. You have to lead enemies due to the absurd projectile system. Disregarding these mechanics you still have to deal with the stupidest AI system in decades. If you hide behind a box enemies will run toward and around that box one at a time. They run to the same place so all you need to do is point the crosshair and pull the trigger when they come around the corner. One of them even ran backwards around the box. They will even stand still in the open and taunt a clearly superior mech. Did I mention the AI also cheats by knowing exactly where you are behind a wall even though they can't see or hear you?
The introduction of Alpha drones was perhaps the nail in the coffin for the shooting sections. These are just bigger drones that require 5 sticky grenades simultaneously detonated before they die. The first battle against this behemoth even had his dangerous grenades glitching through walls I was hiding behind. You will be dealing with several at once just because the game is so bored throwing normal drones and humans at you. It doesn't matter though as almost every shooting bit in the game is a disaster. The only enjoyment came from when you actually get to control the drones for some short segments. This includes the Alpha Drone who takes out 6 guys with one of his grenades, remember you had to fight several of these.
Riddick is not a good game and it certainly isn't a good shooter. Certain aspects of the first person stealth work really well. There just isn't enough depth for stealth to be the focus for the entire 6 hours and instead you need to deal with the poor shooting and brawler elements. Bad pacing, predictable sections, dull fisticuffs are not elevated by the impressive voice cast. Dark Athena is not recommended unless you simply love the Riddick.