The reward of course

You looked down to see that the plaque that was on the base of the pedestal had begun to move. It had been hit with a few stray streaks of semen, but it began to open from the bottom to reveal a small alcove hidden in the base. within was a small black key, difficult to spot with only the light from the rooms torches.

"Well at least all of that wasn't for nothing" you say in an attempt to rationalize your behavior. Just then, you spot another inscription on the inside of the lid.

Though this day you forced my cock to yield, know this door was never sealed

Seriously! The realization sets in that if you would have checked the plaque a little more closely, you wouldn't have had to go through that. Or maybe you wouldn't have gotten to. You do your best to wipe away the remaining sperm from your body, manage to get to a point that you could consider clean. You pick up the key and head to the large door.

"Well there's no keyhole, so what am I supposed to do?" you ponder to yourself. But as you get close to the door, the key fades into dust. As the door begins to open by itself, your inventory screen opens to display a message

-LEVEL 0 COMPLETE

Level 0? Just how many levels are there? You ask to nobody in particular.