Let's just say that it's free for a reason. The idea is to kill every hostile NPC in each level, and move on. There's also harmless NPCs who you don't need to kill, but in certain levels there's a ton of them and everyone looks the same, so I found it easier to just kill every NPC in the area. It's got none of that crude satire we associate with the series, instead playing it completely straight. You really are just a psycho who kills everyone and everything because it's cool or whatever. Combat's basic as hell, there's a bunch of weapons but the M16 has infinite ammo so I just used that the whole time, with the occasional grenade or rocket here and there. It's short, repetitive, and more tedious than anything. Oh, and my biggest dislike? The final level. Fuck off. I don't care that it's a fake-out, do not play with that. If that wasn't a fake-out this would be getting half a star.