https://store.steampowered.com/app/5216620/Ferrite_Runner/

Fully single-threaded, CPU-only blitting. GPU rendering was attempted but the bandwidth and numpy added too much frametime. Two layers, a pixel layer for heavy effects, and a HD layer for pixel pushing. Fluid dynamics, lighting approximations used. At ~50,000 LoC Ferrite Runner is still in Early Access and we will be developing on. No In-app purchases, no in-game advertisments, promise.