Two games in one, too bad only one of them is any good
The guards weapons are encoded to be used only with their DNA, so prisoners cannot hijack or use guns, thisis why you must rely on melee. There are lots of melee weapons to use, such as knives, shivs and screwdrivers. Hand to hand combat looks awesome from the first person perspective, especially the instant kill counterattacks and finishing moves.
Butcher bay is divided into several areas, such as prison blocks, recreation yard, feed ward or mining area. The game čets you backtrack across those areas , and speaking to all of the prisoners is something that makes Riddick stand out from other FPS titles today. You can get jobs from prisoners, so you have to keep checking your mission log and map locations every time you wanna attempt them. Most of the jobs require you to find an item that will help you escape. There are plenty of conversations, sneaking around and completing missions that make Butcher Bay a very fun game.
Unfortunately I cannot say the same for Assault on Dark Athena. This one seems to be just another corridor shooter. You will be given guns early on, unlike Butcher Bay where the shootout begins at the near end. The game will often throw many guards you way, and you cannot sneak by or take them down with stealth. Instead they are instantly aware of you and charge in, and this will continue for many hours. The areas all look the same, while they are nicely detailed and look great, you will get tired after going through the same looking area over and over. Dialogues are also pretty much non existant in Athena and the whole story isn't as interesting as in Butcher Bay. There is also a lack of side jobs to obtain and complete. With all the shooting and no sneaking and talking, Athena feels downright tedious and boring to play.
Multiplayer modes are also present, but nobody seems to be playing it anymore so I cannot say how it is, but you can take a wild guess why that is. You should try Escape from Butcher Bay, everything else you can avoid.