Most browsers nowadays support hardware acceleration (including Chrome and EXE wrappers based on it). That means it's perfectly capable of drawing in HD, since the rendering is offloaded to the GPU in exactly the same way native engines would.
Most desktop systems nowadays also have enough RAM and VRAM to fit entire games in memory at once, although we're planning some load-by-layout features anyway (mainly to help mobile, but it will also help very large desktop games).
I'd recommend making a prototype - whip together a demo of what you're after and see how it runs. Make sure you have an up-to-date graphics card driver though, so you're not getting software rendering. (In Chrome, you can check its status in chrome://gpu)