Very creative, but needs some improvement
As a fan of Pokémon and a HUGE fan of Left 4 Dead, I was very impressed that you came up with such an interesting idea. However, as an audio production major, I feel that there could've been some significant improvements with the sound levels. Your selection of Pokémon music to accompany certain parts of your animation was really well-timed (i.e. when Louis takes the pills) but when I started watching the animation, the music was at a comfortable volume but then out of nowhere that first hunter sound effect came in and almost blew my ears off. Perhaps you could've increased the music volume or lowered the volume of all the L4D SFX a lot. Also, you might wanna look into applying some bit distortion to the L4D sound effects to give them an authentic 8-bit sound so that the Pokémon music and Left 4 Dead SFX have a very similar quality to them. However, as far as art and animation goes, you pretty much nailed it. It's perfect for this animation. The sequence of the battle was excellent as well. Great job!