After more than two decades of progress we have ourselves a sense of history in the video gaming world.  Old favorites have a habit of popping up in new adventures, blocky pixels of love and all.  Over at Ask Metafilter there's a discussion going on that seeks to chronicle old games hidden away inside new games, such as Nintendo Entertainment System favorites buried in Animal Crossing or Maniac Mansion's appearance in Day of the Tentacle.  It's interesting reading as game fans dig deep to come up with additions to the list.

One of my favorite recent old-in-new occurrences is from the new Nintendo DS adventure Castlevania: Portrait of Ruin.  One of the most powerful special attacks in the game summons the spirits of legendary Castlevania heroes, calling on Trevor, Simon, Richter, and Juste Belmont to briefly join the battle and inflict massive damage on the undead.  The characters appear on screen in their original visual formats, be it simple 8-bit pixels or more recent detailed color shading.  It's a fun reference to gaming history (and an excellent attack to use on large imposing monsters).