You were right, the value is the number of seconds until the game will attempt to clear the corpse. However, if the corpse is currently near/in view of the camera, it will not be cleared. That's why you never see a corpse disappear when it's in view. When you scroll the camera away then go back, the corpse is magically gone :) So 7200 would mean the corpse would disappear only after it has been off of the screen for two hours :) For those that want to mod this without delving into the hex, I've created an easy to configure mod with this feature :) XCOM: ToolBoks From glancing at that code, it looks like the +1 you refer to just means, "how much XP is required for MyCurrentRank + 1 (next rank)", not by how many ranks you can be promoted in one mission. If there is such limitation (and I suspect there is), then I like your idea though :) Daemonjax wrote a tutorial on an example mod which might help you get started :) thanksfor the link and there is a limitation I did a mission with one soldier 12 kills (sectoids) and he only got a squddie rank while a sniper with the same amouts of kills but with more missions is a sargent