Lame. Not because it's 8-bit. I think it would be funny as hell to see a real translation of L4D to NES style, but this person totally missed the point. I mean, good lord, it's just a standard isometric shooter. The zombies just stand around most of the time, and having the same hatless-Mario sprites for nearly every zombie isn't all that impressive. Plus, the other characters are totally absent. What the hell? I know, I know, programming AI is hard. But you know what? Flash programmers do it just fine all the time. I've seen tons of Flash games out there that have perfectly functioning AI from NPCs. There's no reason not to have all the characters there, or at least fully functioning zombies.
Really, the only novelty of this is just the idea. NES Left 4 Dead. The graphics are unimaginative and uninspired, and that's not because it's 8-bit. Oh no, I've seen some seriously nice colorful graphics in a lot of NES games. Castlevania III had beautiful, colorful graphics, yet it still pulled off the creepy, dark atmosphere. The gameplay is far too simple. The music was alright, and the fact that he made it so close to the original music is pretty cool. But really, it just draws out the blandness of the game. Having such good music would have made it fantastic if it was actually a good translation.
My problem is that this is far too gimmicky to make it worthy of play. He only got people to play this because it has the name Left 4 Dead on it.