The Show NSFW button is currently showing both "paid" content and NSFW content when clicked.
Playing the project in the itch.io browser will show the base content. Clicking "Show NSFW" will show the content of a "paid" version (in the future, it's a mess right now smh) and NSFW content. Click "Hide NSFW" and any explicit content will disappear, while the "paid" stuff will remain.
The "paid" content is in purple, the NSFW in red, the spoilers in green. The color difference is to visually highlight the amount of content difference there will be from the itch.io browser version in the future from the paid version when it's available.
I'm thinking the base paid version will come with a NSFW button, but it will be basic.
There will be an actual downloadable "Say you're over 18"-to-order-this file available for purchase. All reasonable prices.