About UFO: Aftershock

destructible environment - easily goes unnoticed as you require some heavy firepower to accomplish this and it tends to bug more often than not, so it isn't very useful. The most common way for this to bug is when a door is destroyed, making the doorway unusable for some mystical reason, often trapping your squad somewhere. I've yet to see a case where this actually opened a path for the units to move through (they can shoot through the broken wall sections, though).
irregular grid / spheroid world - the "geoscape"