Good
The animation is great. Glancing at this flash briefly may give the wrong idea that this was hastily animated. Don't be fooled. The animation may be slightly choppy and lacking detail in the beginning, but watching it to the end will put into perspective how much time was spent making the artistic direction of this flash go just the right way. Around one third of the way through the flash, events start to increase in pace and details become more apparent in crucial moments of the flash. The surreal place the protagonist is in when the fight starts gaining momentum is filled with lively backgrounds which really contrast with his and the shadow creature's mostly solid textures. Visual effects such as the screen stretching when he's jumping quickly into the portal and the interesting effects and backgrounds on the other side of the portal such as the scene with the "PLAY" button in the top left corner add character to the setting. All of the weird settings keep the fighting entertaining and visually pleasing as he and the shadow creature fight to the death.
The music is great. The lyrics and speed of the music match up well with the animation. In the beginning, all is calm in the animation and music and it builds up around the time the shadow creature shows up. Both slow down and speed up again as the creature is seemingly killed and then comes back for vengeance.
The plot is good. As with the animation, the plot matches up well with the music. It's as though the song was telling a story all along that has now come into full view thanks to the animation.
Great flash overall. This could easily be the official music video.