Only the flashing effect from the cannon shot and when Elliot slaps you, it's toned down. Other than that, no other filtering.
Maybe we should have another thread specifically discussing the core roms, any changes, and how they 'function' as in Canoe is reading them/running them? To try to figure out why this hires mode works in core games, but not necessarily in external dumped roms from carts.
Maybe it can lead to opening up compatibility to even more games if we can figure out why they function differently than other roms. We might discovery some 'patches' that might be modified to work with other games, that will add compatibility, or fix the same games (from external roms) so they run correctly, but without the epilepsy patches, or any other censorship.