This script combines a couple of features to make reddit a significantly more enjoyable experience.
First and foremost, you can browse through posts with the simple push of a button, either by clicking the left/right arrow keys on your keyboard or by clicking the buttons at the bottom right:
You can also click anywhere in the light gray area to open/close posts easily, which smoothly scrolls your browser view to the post. This also works for comments. No more awkward pinpointing at miniature buttons and tedious scrolling!
Last but not least, this script automatically redirects you to the old.reddit.com subdomain if you happen to land in the new layout. This is mostly because that's only where it works so far, but also because I still can't get used to it and will probably stick with it until they completely kill it off.
P.S.: For the best experience, install Reddit Enhancement Suite and enable dark theme!