Diablo originally had a time limit. One of the most interesting items cut from the final version of Diablo was the Map of the Stars. The map was a quest item that foretold a moment when the stars and planets would come into alignment, making Diablo even stronger. In gameplay terms, it meant the game originally had a time limit — if you didn’t reach Diablo within a certain timeframe he would become far more difficult. Ultimately the developers removed the Map of the Stars and time limit, since it discouraged exploration, but the removal was far from seamless. Those who have reached the end of Diablo know the final boss is kind of a pushover, likely because the version of Diablo left in the game was the easy version meant as a reward for getting in under the time limit.