Complex sentence: The girl on the left smirks conspiratorially at the viewer, making us complicit in the proceedings, and the shadowy uplighting adds a sinister dimension to the scene, suggesting that something unnatural is going on, as indeed it is.
Split into simpler sentences: The girl on the left smirks conspiratorially at the viewer, making us complicit in the proceedings. The shadowy uplighting adds a sinister dimension to the scene, suggesting that something unnatural is going on, as indeed it is.