I'm used to traditional inline 4 cylinder engines, where a crank is way down at the bottom splashing through oil and pistons up top away from the stuff!
Thinking about my boxer 4, I thought why isn't the oil sloshing up behind the pistons, as that 5L I pour in at service time must be sitting somewhere!
In the image below (99%) sure this is a Subaru EJ something something style motor, where would the oil level sit with the engine not running, and when it is pumped around the engine, where is it going? Because 'up' to the heads/cams is actually more like sideways to get there? And gravity isn't helping it drain back that quickly being horizontal?