Because it took so long to get this patch out to fix this issue, Terminal Reality is providing a guide written by their QA team that gives players a step-by-step walkthrough guide to get those missing four achievements so that players who still have the game can finally obtain all 1,000 achievement points out of the game.
While Terminal Reality does not explain what took so long in getting the patch out, they were quick to point out that they do have a sequel coming; it is called Sanctum of Slime, which will be a downloadable Ghostbusters shooter that will be coming next year for the Xbox 360, PlayStation 3 and PC platforms.
Get the walkthrough guide for the glitched four achievements here.