This randomly came up in a conversation today...

I respond to a control check with Vegas Mask my opponent responds to dead for 1k years can I respond again w/Vega's mask in response to Dead?

No, once Dead responds, unless you can respond to Dead itself, it will resolve and blank Vega's Mask, preventing further usage.

I thought responses immediately resolved themselves, as much as they possibly could, and that they effectively worked just like Enhances in that regard -- the entire enhance phase is basically just a response window for E abilities.

You can't, for example, fire off Vega's Mask, get hit by Grim Stride, then keep shooting the Mask until both players consecutively pass on responses to the control check while you're wating for Grim Stride to resolve -- Grim Stride resolves, nukes Mask, and then players continue taking turns responding to the check being made.

I also recall, way back when I was learning this game, that there was no "stack" per se, unless you're resolving a Lost Memories negating a Lost Memories negating a Lost Memories negating a Lost Memories ... where it's LIFO

I think I've been playing Naruto too much.