Terrible, the controls, the game play and the level designs...
Secondly, the game is too easy. Before every boss fight a blue screen comes up and tells you exactly how to beat the boss, where's the fun in that? The bosses themselves are neither strong nor smart, even the more educated ones like Doctor Octopus. They will continue to attack you in the same way until they are out of health. For example in one of the later levels you are on a train with Doc Ock and the entire level consists of him throwing various objects at you and you knocking they away or dodging them. Granted the objects do get bigger but they still are no match for a ball of webbing.
Finally, I come to the controls and believe me when I say this is a big issue. The entire control system is based around your mouse and the arrow keys.
Arrow keys are for movement obviously, but the mouse is for practically every other action that Spidey can do. Point your mouse at a wall and you can zip to it. Point it at a web target and you can swing. Point it at an enemy and you can attack.
The right mouse button is the jump and double jump button. The left mouse button is the swing, zip, attack, web up, un arm, web shot and use button. It means that while your fighting if you accidentally click to attack but aren't facing in the right direction, then you are catapulted 100 yards onto a wall breaking you attack combo.
Overall Spider-man 2 for PC is a game that I would strongly recommend against buying for its lousy game play, its annoying controls and the lack of a fluid swing system.