[v_b]

It is. To be hones I played it now in "hard" and the peformance was absolutley fine.

I know that some browsers has still issues when it comes to pure CSS animations as they are running on the GPU and when the Hardware acceleration is disabled the CPU goes sometimes crazy.

I had the same on an animation GitHub a while ago used on their landing page.

[withinboredom]

Issues seem to be random, it is like the board shifts back and forth to the right/left until it settles, causing performance to tank until it settles.

[ALittleLight]

Performance seems to get worse about midway through. I assumed it was an intentional difficulty increase though.