SLUDGE (standing for Scripting Language for Unhindered Development of a Gaming Environment) is a system by which anyone (within reason) can make an adventure game. It runs in any recent version of Windows and now also on Mac OS X and Linux. It's high-res (any resolution you want) and uses 32-bit colour. To make your own SLUDGE games you'll be needing the SLUDGE Development Kit; to play the games, the SLUDGE Engine is required (it's included in the development kit download and should typically be distributed along with the games). SLUDGE was originally created by Hungry Software and is now free software! It is licensed under the terms of the LGPL (the GTK+ Dev Kit under the GPL) and the source code is available for download.