Some of the best you can find in terms of first person shooters. Great map variety, great guns, lots of enemy types and some of the best boss fights in FPS games. The only bad thing is the writing if you don't like dumb humor. Because all the humanoids in this game take turns on who gets the one braincell in the universe. But you can very easily skip all of the cutscenes.

It also has actually fun vehicle segments that aren't too prevalent, keeping them interesting when they appear. There's a lot of fun gimmicks thrown in the mix for levels generally too. Like some levels where you are forced to speedrun them and a "freezing" mechanic where you need to move in and out of shelter.

I never understood why this game is considered the worst in the series. If I were to guess, it's how much gameplay variety it has and the fact it's long. That and how stylistically different it is from every other Sam game.