If your charging a unit that is in terrain you would end up in the terrain - so negative results of charging into terrain. However it seems that you do not have any negative on the charge modifier.
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Also charging into terrain, if you lack grenades (I assume that this works the same still) you should still suffer the I penalty, as far as I can tell...
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Also charging into terrain, if you lack grenades (I assume that this works the same still) you should still suffer the I penalty, as far as I can tell...