Complex sentence: A bonus round was played by the contestant towards the end of the show in which they had to identify ten words with only three letters each to work with (for example, BTR for "betray"), with only five seconds allotted for each word.
Split into simpler sentences: A bonus round was played by the contestant toward the end of the show in which they had to identify ten words. The contestant was shown only three letters for each word (for example, BTR for "betray"), and had only five seconds allotted for each word.