Additionally, in the archive, besides the usual Gem, there is also Gem2 — a serious rework for the St. Petersburg tournaments.
Of course, you should play the original Gem. As for Gem2, only by mutual agreement and in TE-full (it's tailored for it). Although the gameplay there is certainly many times more substantial.
And one more thing — if there are any troubles with TE maps, the universal algorithm for solving them is as follows: take a SoD map, open it with the TE editor (h3wmaped.exe, not to be confused with the SoD h3maped.exe) and save it under a different name. That's it.
You can start in TE using a SoD map, but you shouldn't. I tried it once, and bugs started popping up. You need to resave them; apparently, their formats differ slightly.