Thanks for all the comments and suggestions, guys!
One question, though: I've noticed that none of the people claiming the game is too easy has actually finished the game in General mode. I did design Sergeant mode to be easy, after all. I'm not trying to be snarky or anything, I'm genuinely curious: should I put a warning on Sergeant mode saying it's easy, remove it altogether, or really ramp up the difficulty on Sergeant so that it's closer to General?