Underwurlde, the second game in the Sabreman series of titles from Ultimate (between Sabre Wulf and Knight Lore), has three separate exits, each naming another game in the series.
[1] The first exit names Knight Lore, which was released at the same time as Underwurlde.
The third exit names Mire Mare, which was expected, but never published.
[2][3] On completion of Knight Lore, the poem displayed reads: On completion of Pentagram, the message displayed is: Rare (the company that rose from Ultimate's ashes) revealed in the late 1990s that the game would have been similar to the top-down Sabre Wulf.
[4] They also explained that although the basic game design was completed, Ultimate's hectic schedule meant that the title's actual coding was never completed.