Just completed a Nuzlocke runthrough on Red. Was probably one of the most fun playthroughs of the game I'm ever done really.
Ended up taking a few really bitter losses along the way. Beedrill and Raichu went quite early but helped, but it was Saffron that really did me in for a while. Lost Charmeleon in the Fighting Dojo just before he was about to evolve in to Charizard, then Raticate and Graveler in Silph Co.; all three of those had been in the team since very, very early on and had helped a load along the way (particularly Raticate. Hyper Fang is a beast).
After that though, I had a bit of a rework and ended with a team that was Fearow, Gloom, Vaporeon, Gengar, Snorlax and Hypno. Got them through Fuchsia-Cinnabar-Viridian, then lost Snorlax in the pre-Victory Road battle with Blue. Had a Weezing on standby though, so ended up going in to face the E4 with my usual team, all around Lv. 45-46.
Yeahhh. I forgot how strong the E4 were and how many levels they were ahead of me. Lost Fearow in the battle with Bruno, but carried the five remaining in to Blue. Lost Vileplume pretty early on and Weezing deeper in to the battle, but ended up winning with Vaporeon (48), Gengar (47) and Hypno (47). Was all kinds of fun though. Tempted to do one for the other games in order now.