I loved
Danton's Death, but I'm biased. Favourite period in history? Check! Oram on design? Check! Cork on sound? Check! Austin on lighting? Well, no, but Constable is an acceptable alternative. Toby Stephens impersonating Eddie Izzard? Not what I usually look for in a play, but why not! I expected it to be among the worst things I've ever seen, and was pleasantly surprised when it... well, wasn't. XD
As for the trick, I don't know if you've ever seen
The Prestige? My current theory is that they did the trick here the same way they did the big trick in that movie.