Despite the fact that it's technically a bad thing, the Eclipse Cannon's laser blast was totally awesome.
Shadow gets one of these moments in Shadow the Hedgehog. His past gets revealed (Black Doom is essentially indirectly responsible for all the pain he's suffered in his past.) The way he decides to put his past behind him (and take revenge against Black Doom) is just awesome. Blasts a bloody swathe of destruction against countless aliens that got in his way, turns super, kills Black Doom in his Cosmic Horror arch demon form (complete with blowing his wings off), teleports the Black Comet onto the path of the Eclipse Cannon, and basically ensures that not a single Black Arms creature survived his wrath. Awesome.
Shadow: I am Shadow the Hedgehog. I've left the past behind me. No one can tell me what to do now! I will destroy you, Black Doom!!
Shadow's reply to Black Doom's Hannibal Lecture? "You're boring me to death, Black Doom!"
After Black Doom's control of Shadow is broken due to Heroic Willpower on Shadow's part, they both transform (Black Doom into Devil Doom, Shadow into Super Shadow.) and fight in the skies and Shadow wins by hitting him with Chaos Spear repeatedly in his eye.
Super Shadow then uses Chaos Control to teleport the entire comet back out into space. After this, he uses the Eclipse Cannon to destroy the Black Comet completely.
When finishing the pure good or pure bad ending on their dark paths, Shadow stands over a battered Sonic and proclaims himself the best. Badass!
In the neutral endings, Shadow manages to take control of Eggman's entire empire, and claim the emeralds. And the only help he had all along is Omega.
Look at the spaceship Sonic uses to give Shadow a lift into space. It's got Tails' Tornado on the front. TAILS TURNED HIS PLANE INTO A SPACESHIP. How is that not awesome?
This gets a nod in season 3 of Sonic X where Tails converts his X-Tornado for the same purpose. It was so awesome, he did it in two separate continuities!
The FMV opening sequence to his game. Not only does it have super-smooth, beautiful animation, but it perfectly showcases Shadow's badass factor. Not only that, but introduces you to the conflict you'll face in this game- the invasion of the Black Creatures, the war between them and the forces of G.U.N., Shadow's contemplation of his true identity. All backed by the fitting, epic rock song I Am...All of Me performed by longtime Sonic theme performer Crush 40.
Space Gadget allows for a rematch between Shadow and Sonic's race. And, for the hero route, Shadow wins.
Props must be given to GUN for Diablon, which is well-made enough that, in combination with Sonic, it makes a very good counter to Shadow. Shame about how Shadow can take advantage of that...