I grabbed all the sound effects either from an online sound library or from Youtube. Snake and Bowser are both ripped from a screenshot taken within Super Smash Bros. Brawl and then masked in Photoshop. The exclamation mark that appears above Snake is also ripped from Brawl and masked in Photoshop. The background was taken from Google--I'm not sure what it's from, but it looks video game-y.
All layers are 3D, with Snake and Bowser being placed closer to the camera than the background. Shadows are also on. I keyframed the spotlight to move across the screen and then come back fast on Snake. I then zoomed the camera and changed its point of interest as well as added an ambient red light. I made the alarm fade in and out by making a bunch of 100% intensity and 50% intensity keyframes and then spacing them out evenly. As Bowser hits Snake, I went frame-by-frame and altered Snake's scale and positioning so it looks like Bowser crushes him. The Game Over screen and audio was ripped off Youtube--I set its opacity at 50% to seal the deal.
I used Foam effects for the two ghost variants. The smaller ghost, Boo, was given an increased wind effect to make them blow to the upper right corner. The larger ghost, King Boo, was given greater difference in size.
I created a title, then imported a fire background and placed it on the layer below the text layer. Then I put a Shatter effect on the background, altered the camera angle a bit, extruded the title, and set the force options all to 0 so the text doesn't actually shatter and instead just retains the 3D effect.
With the 3D effects in place, I keyframed the text from offscreen to crawl onscreen in around 4 seconds.
I lit Diglett using a directional light with a slight yellow tint to match the background. I also bumped up the intensity a tad and used depth map shadows.
I used the shape tool to make rectangles and then auto-traced them to create masks. I inverted the masks so Bowser appears when he passes over the rectangles.
I downloaded a rock bump map online and applied it to the spheres around Diglett. The panorama is an image I got from Google. I also use paint effects to lay down a few daisies around Diglett.