This is one of the better games when it comes to gameplay. The game is not an all-out first person shooter. It's the rare kind of game, which combines hand to hand combat and shooting. Also there is something called as stealth mode to ensure enemies do not see you as you sneak up on them. As with most games it comes with 3 difficulty levels: easy, medium and hard. But mind you easy is not a walk in the park. You still need to use stealth to survive in the game but you can engage in open shootouts. In hard mode, engaging in open shootout is suicide and guarantees that you will end up dead. The game has some nice 3D real time rendered cut scenes. Most conversation is also wide screen movie type. This gives a movie type feeling to the game.

The game has relatively small amount of firearms and not all of them are available to begin with. Each level is designed to be completed by a particular set of firearms like the pistol, shotgun or assault rifle and hand weapons like shims, shives or knuckle busters. There are places where you need to engage with heavy arms. This makes the game more enjoyable.
The game AI is superb. The enemies duck and take cover when you are shooting. And it all looks realistic. The AI is clever enough to dodge your bullets and take cover. They ask for backup and in most cases they do not come running towards you and fall like pins. Instead they try to attack you from 2-3 different directions. This is observed in normal and hard mode in particular. In easy mode you can get away sometimes.

At the start of the games you cannot use guns. The guns at butcher bay are DNA encoded. So only soldiers can use those guns and it gives a shock to unauthorized user. But don't worry. Its Riddick you are playing as after all, he will manage to get himself weapons. And remember, you do not have unlimited ammo. It's nicely balanced. So wasting your ammo is not a good idea. Whenever possible use stealth mode and kill 1 enemy at a time. For stealth kill you need to be in stealth mode and sneak behind the enemy. Then you can either break the neck in single go, which is louder and will attract any close by enemies. Or you can slowly break the neck, which takes slightly more time but doesn't make noise. Also there a perfect headshot that insures single shot death to the enemy. There is no sniper weapon but with practice you can snipe using the regular assault rifle or pistol and its a must in hard mode. There is a flashlight on guns. It can be helpful in initial stages where you don't have power to see in the dark. But the flashlight will attract enemies. So turn it off when you hear the enemies talking.