Finally watched them, back-to-back:

Grindhouse is the double-feature featuring:

Quentin Tarantino's Death Proof (2007) (Kurt Russell, Zoe Bell, Rosario Dawson). IMDb plot: "Two separate sets of voluptuous women are stalked at different times by a scarred stuntman who uses his 'death proof' cars to execute his murderous plans."

I loved the classic movie "Feature Presentation" and "Restricted" animations in the beginning, but I have to admit the old film effect, while at times creatively placed, was often just distracting -- in both films. But as for Death Proof itself, I thought it started out a bit slow, but halfway into the second story 'til the end, it made up for it and I loved it! Tarantino style throughout.

Robert Rodriguez' Planet Terror (2007) (Rose McGowan, Freddy Rodríguez, Josh Brolin, Bruce Willis). IMDb plot: "After an experimental bio-weapon is released, turning thousands into zombie-like creatures, it's up to a rag-tag group of survivors to stop the infected and those behind its release."

I don't know what it is, but for me I just cannot take zombie movies very seriously. I have yet to see one that looks realistic at all, but maybe that was the intention (being all retro and all). Nothing really new here, but entertaining nonetheless.