The XCOM: Enemy Unknown expansion Enemy Within introduces plenty of ways to upgrade your forces, but from the sounds of it, you're going to need them. Aside from the genetic mods and mech suits, the new currency named "meld" is designed to make you take more risks in combat.
Meld canisters are hidden throughout each map, and a countdown timer begins when the mission starts. If you don't find it in time, it explodes, forcing the player to choose between approaching cautiously and potentially losing the meld, or pushing hard and increasing chances of finding it.
"For players who have settled into a very conservative play style in which they maximize their soldiers' safety and they only use the best cover, that will hinder you from recovering the most Meld," lead designer Ananda Gupta told The Escapist. He notes that two canisters are hidden in semi-random patterns in each map: one in an easier spot to reach, and one that is much tougher. Conservative players will still be able to get a little, so harder difficulties that require caution won't miss out completely.
Enemy Within will also be making a host of small usability tweaks based on player feedback. As detailed to Polygon, those include easier inventory management, and the ability to create your multiplayer squads offline.