Desktop (Chrome, Windows 8.1, Intel Pentium Dual Core E5200 2.5 GHz, NVIDIA GeForce GTS 450 1 GB, 4 GB RAM):
~40-60 FPS regardless if the front-to-back renderer is enabled or not
Mobile (Samsung Galaxy Note 3 (SM-N9005), Chrome, Android 5.0):
~30-50 FPS with the front-to-back renderer disabled
~25-30 FPS with the front-to-back renderer enabled
The game I tested on is a 2D metroidvania platformer.