300 mb, but that's not really a useful number to give you, because:
"Construct 2 displays an estimated memory use in the status bar. You should keep an eye on that. The estimate is based on the largest layout's image memory use, plus the memory used by two images the size of the window (which will probably be necessary by the OS or engine rendering system). With good image re-use, it should be easy to keep this under 60-80mb."
I have a layout where I've been sticking most of the objects from the game, so the memory use is listed as much higher than the game ever gets to when it's actually being played if layout by layout loading is working. Since it isn't on cocoonjs, the decompressed memory usage of the entirety of the current c2 version of loot pursuit, which probably doesn't even have half the graphics of the whole game yet, is probably somewhere around 400mb.