Since you mentioned "developing a feature," it’s worth noting that the developers (Teyon) actually added a massive after launch called Infiltrator Mode .

You may be searching for the playable demo to try the game before buying. Feature Highlight: "Infiltrator Mode"

You might be looking for "free" community-made DLC or mods that add features to your existing game download.

You are dropped into a map and must eliminate Resistance forces to find the location of a specific target.