I've been playing Cortex Command after I got it this week in the Humble Indie Bundle and, for the most part, I think it's quite fun.
However, I'm noticing that when I order a new person/robot/zombie with lots of stuff (a heavy weapon, multiple weapons, etc) they don't go upwards when firing the jetpack. The jetpack is an important way to get around the terrain considering it can be destroyed and is a giant pain to walk around on. I think I'm interpreting an icon on the screen as "overburdened" when I fire the jetpack which explains why I can't take off, but the game is much more fun with use of the jetpack. Is there a way to upgrade it or get a more advanced version that can carry more load?