Slitherine

The following strings are needed to clarify the MP new challenge UI:

IDS_ALLOW_REROLLS, "Allow Restarts",
IDS_REROLLS_PERMITTED, "Restarts Permitted",

Tooltip text:

IDS_TT_ALLOW_REROLLS, "Allow game to be conceded during either player's first two turns, without it being scored for Elo purposes. This is permitted in some tournament systems to allow the challenge to be re-recreated with a new random map.",
IDS_TT_RANKED_GAME, "Include result of challenge in Slitherine's Elo ranking system.",
IDS_TT_PAIRED_GAME, "The challenge will be set up twice, on identical maps, with each player commanding Side A in one version and Side B in the other.",

This is what I have so far:

IDS_ALLOW_REROLLS, "Permitir reinicios",
IDS_REROLLS_PERMITTED, "Reinicios permitidos",
IDS_TT_ALLOW_REROLLS, "Permitir que se conceda el juego durante los dos primeros turnos de cualquiera de los jugadores, sin que se puntúe a efectos de Elo. Esto está permitido en algunos sistemas de torneos para permitir que el desafío se vuelva a recrear con un nuevo mapa aleatorio.",
IDS_TT_RANKED_GAME, "Incluya el resultado del desafío en el sistema de clasificación Elo de Slitherine.",
IDS_TT_PAIRED_GAME, "El desafío se realizará dos veces, en mapas idénticos, con cada jugador al mando del bando A en una versión y del bando B en la otra.",

What would be the correct translation of "Side A" and "Side B" in this context?

Please point out any other errors.

I think your translation is good and clear. I would only change the word "Incluya" to "Incluir" ("Incluya" would be used if you were prompting someone specifically to include something, like "Please,(you) include..." which would be translated to "Por favor, (usted) incluya...".)

I would also change "Permitir que se conceda el juego durante los dos primeros turnos de cualquiera de los jugadores..." to "Permitir que cualquiera de los jugadores se rinda durante los dos primeros turnos...", for consistency since "concede" is traslated as "rendirte"(surrender) in the original spanish translation.

As for Side A and Side B, I would also use "Bando A" and "Bando B" for consistency since it is what is already present in the game if you play in Spanish (Although I would have originally used "Lado A" and "Lado B"). I hope this helps. Anyway, if you need any more help, let me know.

Thanks