It is an older macbook pro with an 2.2 GHz Quad-Core Intel Core i7. I tried using your test page and still get this error once I click confirm on the order of my squad.
I had the same error. particularly when toggling from full screen to small screen during battle. the testing branch ran more smoothly, but had the same issue. by avoiding toggling screen size during battle i made it to the mini boss but my cat hit esc :(
