I wish I had more to say about Heidelberg, but I was pretty limited in what I could physically get myself to do at that point. However, a couple items to mention...
First, the Schloss / fortress is as cool as its reputation. Overlooking the town (don't they all seem to?) and partly in ruins from being taken so many times, the fort has inspired many over the years. One purportedly is the philosopher Hegel, who looked on it many times on the "Philosopher's Walk" leading up the hill on the opposite side of the river.
Below is the view of the old town from the fortress. The old bridge and Philosopher's Walk is off the photo to the right, and perhaps after the trip I'll post a photo including those.
On my way to the fortress, I passed the Heidelberger Zuckerladen, which was a candy shop my guide book recommended I find a way to get to. The front window display has a dummy in a dentist's chair with a bunch of rotted teeth/dentures lying at the bottom of the display case. Not your typical intro, but ok.
Inside I was told I could not take photos, and the owners helped me pack up whatever I asked for. You probably already know Germans are big fans of gummi anything, and there was a lot to choose from here. I got a pick-a-mix sort of selection and some truffles and left it at that. Then, the owner asked me to guess "high or low." I guessed low, then she rolled some dice, and if I guessed right, I would get an extra prize. I guessed wrong, but since I rolled three 4's, I got some extra gummis anyway.