He's already been described thoroughly, but I'll throw in my experience of watching him as he was my favorite player ever until Datsyuk came along.
First off, he had such swag to him. And I'll get to that more in a minute...
His skating has been mentioned and should probably be the first thing mentioned when talking about him. He was fast and explosive, but also powerful. So it wasn't just like he was a small speedster who could get easily pushed off balance. He could also power through guys and get anywhere on the ice. Basically a perfect skater who was visually stunning to watch. When you were at the Joe watching him during his peak/prime, the crowd would literally begin to rise from their seats when he'd gather the puck in the neutral zone and attack because you felt like he was going to create something.
That last point brings me to the next point. He was basically an automatic zone entry. He was too fast, too skilled, and too strong on the puck for teams to regularly stop him on the entry.
His shot was a rocket. He could and did play the point on the PP and could beat goalies from the blueliner with his slapper. He could also score from the circles with his wrist shot. His most common move though was attacking from the right side of the ice with speed and then cutting in on the defencemen. They knew it was coming, but it still always felt dangerous.
Defensively, he was positionally sound, but his best asset again came back to the fact that he could skate like the wind. When you add flawless skating onto a defensive mind with a great poke and sweep check, good luck.
So when you put it all together he was essentially a perfect hockey player at his best. He had all of the tools and in baseball terms he was a 5 tool player.
As I mentioned early, swag. So now that you know he was fast, powerful, and skilled, imagine it all with a sick head of hair flowing out of his helmet, a blue undershirt, and some sweet Nike gear. He was the man on and off the ice, where he dated high profile babes and drove Ferraris.
So with all of that being said, you can see why it's somewhat frustrating that he didn't dominate more. His 94-96 seasons should have been closer to the norm. Only having two Top 10 point finishes is - truthfully - disappointing given his skillset. And even as his biggest fan during his Detroit tenure, I can admit that there were times where I didn't understand why he wasn't more consistent at that peak level. Because even though he never had seasons quite like 94 or 96, he would still have individual games and stretches where he was just as good and looked like the best player on the planet. But more often than we'd like to admit, he'd go stretches where he would have minimal offensive impact.
To close it all up, I'm glad that somebody mentioned the Russian 5. They were truly poetry on ice and looked like they were playing a different game from everybody else. 5 Sedins was a good way to put it with their chemistry and cohesiveness. Those were the days.