If you have played either Crusader games, you will be right at home with Total Mayhem. You explore the world from an isometric perspective, shooting anything that moves and a few stationary objects to boot. Along the way, you also have to solve the occasional puzzles using keys, trap doors and hidden entrances to complete the objectives for each mission. As the game progresses, both the bad guys and the arsenal at your disposal grow in power. In these respects, Total Mayhem and Crusader are identical.
The two games differ in the details, however. Total Mayhem allows you to control up to six soldiers (cyborgs, to be precise); Crusader has only one. Total Mayhem also lacks the gratuitous graphic gore found in Crusader -- persons running about on fire screaming, welling blood under dead bodies, and so on -- because the opponents in Total Mayhem are robots. When a cyborg under your control dies, the soldier simply blows up in metal chunks.
The interface for controlling six cyborgs is confusing and never really intuitive, although after some practice you will get used to some of its quirks. The range of options are not very large, though, and any cyborg you don't directly control basically become dummies waiting to be shot, unlike the "intelligent" squadmates in Terra Nova: Strike Force Centauri or the space marines in Space Hulk. If you are willing to invest the time and patience in a game, and to shift from soldier to soldier every few seconds, Total Mayhem is worth a try. It's not a worthy successor to Crusader games by a long shot due to poor interface and bad AI, but it's somewhat enjoyable if you have a high tolerance threshold.