HOW DO YOU IMPROVE upon perfection? Easy: You don't.

This holiday season sees remakes of cult classic PC shooter Serious Sam as well as quirky platformer Earthworm Jim. Both of these original games still boast rabid followings, and it would have been easy to upset either fanbase. Yet the remakes' developers have somehow pulled it off—the two resulting games should appeal to new fans and old purists alike, and not just because of their sub-$20 price tags.

While both remakes add something to the original, it's also worth noting exactly how little content they introduce. The only thing approaching "new" content would be the online leaderboards; otherwise, Earthworm Jim HD is identical to its 1994 Sega Genesis predecessor, just as Serious Sam HD is, content-wise, a direct translation of its 2001 PC iteration.

Perhaps the new Sam's success is simply a case of less is more. The original Serious Sam was an intentional throwback to the days when shooters (specifically Doom) rarely bothered with plot. You were given a gun, pointed at some monsters, and you kept firing until everyone else was a corpse. That "purity" was Sam's key feature, and tacking on extra complexity would run counter to the game's inspiration. By merely rebuilding the game's aesthetics in high definition, publisher Majesco has kept the Serious Sam spirit intact. As always, it's a stylish, frenetic gunfight that will smooch your adrenal gland for hours.

On the other hand, Earthworm Jim originally succeeded on the strength of its wacky characters and bizarre setting. Its gameplay was consistently novel yet intuitive, and only Super Mario World offered as much variety in a platformer. Change any of that and you may ruin what made the game so special in the first place. As with Serious Sam, the choice to "just" rejuvenate the original's aesthetics ensures that a new generation can appreciate Jim's bizarre quest, while the purists who enjoyed the original won't immediately dismiss the game based purely on its looks.