Apart from its trademark blood and gore there is not much of SoF left in Payback.
I definitively don't object to mindless FPS games like SoF Payback if the FPS part is done right. So what went wrong?
First, graphics/video in this game are OK, but shadows rendering is an example of how NOT to do things. Due to a really lousy shadows job, 5 or 6 year old games look better than Payback ... and some of them much better.
Second, blood and gore ... well, you can turn it off if you are bothered by it. The funny thing here is that the ragdoll physics are so much over the top and unbelievable that instead of a "wow" or "yuck" factor upon a body dismemberment by a single sub-machine gun bullet the result is usually comic rather than taken with any kind of seriousness.
Third, the game AI is horrible. The bad guys will 2 out of 3 times line up so you can just easily mow them down or after you shoot one of them in the leg (and that leg miraculously separates itself from the rest of the body) 3 or 4 others will came to the exact same spot to be killed (unless of course they stand right next to an explosive barrel and commit suicide by shooting the barrel themselves.
Fourth, game mechanics are so dated that even the simple move as lean left/right was not implemented, not to mention prone, take cover, or anything more complex than crouch.
Fifth, awful game options/settings, especially in the video/graphics department. Video settings ... nothing beyond the screen resolution and brightness. It gives you a rather clear picture that Payback was develop with gaming consoles in mind. Too bad, since many of the visual and esthetic problems could be resolved by tweaking AA, lightning, shadow quality, etc.
Sixth, the AI spawning is awfully timed. In most cases you can look at the spawning spot that's empty, make a step towards the objective and suddenly previously empty spot will be filled with enemies. Kinda defeats any use of the sneak and quietly snipe your enemies away tactics. BTW, the game seems not to be sound aware -- meaning, whether you use a suppressed/silenced weapon or not enemies respond in the one pre-scripted way. It would be nice to have the AI scripted to respond to, say, a loud shotgun attack differently from a sneak and silently snipe attack.
On the positive side there are plenty of different weapons in this game, from a variety of snipers, assault rifles, SMGs, down to pistols. A very nice collection that any FPS game would be proud to have. Many of them also have attachments (suppressors, scopes) that you can mount before the next map starts. The negative side to this is that you can't, say, remove suppressor once the level starts. Also, there seems to be no decrease in bullet impact damage or range when suppressor is attached. One thing worth mentioning for many is to reduce X/Y mouse sensitivity to 4 or even better to 3 so you can actually aim faster without excessive reticule movement.
The weapons sounds are pretty good too. Ambient sounds seem to be OK too, but somewhat too loud even when not too close to the source. Background music, voice acting are on a cheesy side (but you probably won't even notice while trying to figure out where enemy shots are coming from in that washed out, blurred, and awfully shadowed environment).
The other positive is also relatively fast response by the publisher to the reported game bugs by issuing a patch (1.1).
Overall, Payback, doesn't feel like SoF series many people used to know. Apart from its trademark blood and gore there is not much of SoF left in Payback. As a game on its own, Payback could be a source of a rather pleasant but non-immersive entertainment given that the visual quality, the AI, and the gameplay mechanics improve considerably in the future.
(Note: The game packaging is minimalistic ... read=cheap, but also includes a separate SoF Platinum Edition CD. Neither of the games have a serial number, but the CDs need to be in the tray during the gameplay).