Well, I played the game back when it was released and I found it to be a lot of fun. At the time, the sheer amount of explosions and mayhem was incredible, and you could set enemies on fire, which was great. There's sneaking, shooting, crazy-powerful weapons, hijacking mechs and making them wander into packs of soldiers while spewing rockets everywhere... basically just great action. Also you could blow up the environments, including locked doors if necessary, which is pretty sweet.
One thing that disappointed me a little when I played back then was that if you blow up, incinerate, evaporate, or otherwise obliterate a human enemy, then you can't get any money or ammo off his corpse. This means that a lot of the time you may prefer to use "weaker" weapons like machineguns and shotguns to kill human enemies so you can take their money and buy bigger and badder weapons. I think that this problem is probably not as bad as I actually thought then though, as I was younger and likely not as good at games as I am now. I've heard there's tons of secrets and such to find which provide new weapons and ammo too.
I don't remember the music at all but people say it's great.
Controls are a little slow, simlar to the original 2D Prince of Persia titles in their feel. You often have to carefully plan when to move, when to aim and shoot, and when to duck and reload. Most players, including me, recommend playing with keyboard only, although there is support for mouse control. The controls mean that despite the wanton desctruction, the game feels a little more tactical than your average action game. I liked this; I felt fully in control rather than frantically running around spraying bullets everywhere.
Overall, I think it's a solid purchase for $5.99.