Nostalgia for the 1990s seems to have become the stock in trade for videogames over the past few years. I’m thinking of the tongue-in-cheek revisit to MS-DOS’s glory days of Vlambeer’s GUN GODZ (2012) and the brutal, tasteful modern reconfiguration of the 90s shooter in this year’s Devil Daggers. But these are exceptions, as drawing from that well is typically an exercise in diminishing returns. A new shooter, Merger 3D, is testament to this, as it showcases the best and worst of the 90s shareware aesthetic. The title weighs in at a svelte 10 MB, and supposedly will run on every Windows OS…