Since version 1.1.0 it's possible to load an old game. This feature is very much still under development, but this initial version is too convenient for finding/fixing other bugs not to release it.
The idea is that you can now specify an old game number and a decision number on a table. After doing so you can select a player order, which will determine who (on the new table) becomes whom (in the old game you're reloading).
The feature isn't very user friendly yet. You could wonder how on earth you're supposed to know your old game numbers, and how are you supposed to guess the decision number you're interested in. Those would be very legitimate concerns, and will be addressed in later releases. At some point you will be able to specify these 'reload-instructions' from an URL, and you will be able to generate that URL by some special click in a game log.
There is still a fundamental problem with this feature I haven't really been able to solve yet. It allows you to reload a game that was generated by the current server version just fine, but if you want to reload a game from an older version all bets are off. It may very well work, but could also be broken. Hypothetically speaking - Suppose that old server version contained some card bug (Smithy was drawing only 2 cards) that has been fixed on the new version. Reloading that game on the new server will fail very shortly after the first Smithy play.
For now, I hope this will help us solve card bugs more easily (so please do include a game number on all bug reports) and it's great fun for puzzling too.
Here is a very nice one to start from a game Marin and I were playing yesterday: game 1105805, decision 207. Add a bot, make sure you're taking over Marins perspective. The goal is to win this turn, because it's very unlikely you'll get another turn.