One of my goals in creating the Roguelike Gallery was to gain some objective insight into the difficulty of early roguelike games.
For more popular roguelikes like NetHack and DCSS, there is plenty of online data available. For Rogue, the best data we had was the graph in the Rog-O-Matic paper. According to those statistics, a median score of about 700, with one victory in about 60 games, was considered excellent performance.
The Gallery's statistics after 5 years show a similar logarithmic distribution of scores. There are some differences; the best players have medians around 1200, but no one has won, in over a thousand games.
Recently, I changed the score graphs to use smaller categories. Now some graphs show more detail, including some variance from the smooth logarithmic decline. These bumps are much more visible in the graphs of experience level and dungeon level, about which the Rog-O-Matic paper says nothing.
Most games fall into one of two categories: quick death and mid-game, the spike at the left and the bump in the middle. The quick deaths happen on the first three dungeon levels, to mostly XL 1 characters, resulting in less than 500 points. Players who avoid a quick death usually survive to dungeon level 8, 1000 points, and XL 6: the mid-game. However, the Rogue Team increased the difficulty from V3 to V4 to V5. The mid-game group became smaller, and it shifted toward sooner deaths and lower scores.
Of course, more data would make the statistics more accurate, especially for Super-Rogue and Advanced Rogue. Keep playing!