Kerbal Space Program

Not a game breaker, but bothersome to say the least. I discovered this one when I went EVA during the suborbital training mission. My kerbal and the pod got separated, but since I had armed the parachute, it eventually deployed and the pod survived. I was able to steer my parachuting kerbal to within 30m of it before getting to the water. I noticed that when I made my kerbal swim in any direction, he also swam at a downward angle as well. Unfortunately, the shift key didn't work to make him swim up (nor did ctrl make him swim straight down). I was able to get him back to the surface, but only by letting him slowly float back up at 0.1m/s, so it was little bit of a challenge to get him back to the pod. I have no doubt that had I continued moving around in that manner, that I could have made him descend all the way to the ocean floor.

Allowing a kerbal to swim up and down actually is a nice improvement. Just add keybindings for ctrl and shift and allow it underwater.

I will test further to see if this also comes up in non-scenario gameplay. I suspect it will, as it seems to be core gameplay.

Extra: I was not able to get the behavior to repeat in subsequent runs either in the training scenario or sandbox play. I suspect it could have been due to me spiraling in with the kerbal parachute or the particular view angle I happened to be looking at at the time.