Complex sentence: A likely explanation for the multitude of bugs is that the game may have been rushed to meet the 1998 Christmas season, possibly as an attempt to beat "Half-Life" to market.
Split into simpler sentences: A likely explanation for the multitude of bugs, is that the game may have been rushed. The game was likely released prematurely to meet the 1998 Christmas season, possibly as an attempt to beat "Half-Life" to market.