There is a setting in the project propriety, basically C2 by default scales up the texture before rendering them, which causes more work to be done on an higher area of display. this setting can be changed during edit time(even at runtime using a system action, don't remember the exact name of it) so the sprites are not resized before rendering at an higher area of display, which erase the performance loss but will afect how the game looks (fora pixelated game though, I wouldsuggest to have it always like that, since theyreally don't need to be scaled up anyway)