It’s a popular suggestion, I’d like to see implemented:
- Game Mode Idea - Feature Requests and Game feedback - Gems of War | Forums
 - New Mode: Survival - Feature Requests and Game feedback - Gems of War | Forums
 - Survival Mode - Feature Requests and Game feedback - Gems of War | Forums
 - Have a survival. Mode for high end game players - Feature Requests and Game feedback - Gems of War | Forums
 - PvE Survival Mode - Feature Requests and Game feedback - Gems of War | Forums
 - Endless / Survivor - Feature Requests and Game feedback - Gems of War | Forums
 
Among others, I’m sure.
A lot of differences in exactly how players want it to work, but the core idea of a survival mode is the same, and they definitely should add it.