Well, even if no one's commented on those yet, here's another batch to consider myself caught up.
Strip 27 - Control, Alter, Escape

Generally in D&D, feats are something you add to your characters to make them better in a particular aspect or enable them to do something they otherwise couldn't. But you never
spend feats, so the group here is using something more akin to Action Points (a la Eberron) or Hero Points, like we used in the World of Warcraft RPG.
Critical fumbles are also an aspect of D&D which has support in some groups and violent hatred in others. Typically, rolling a 20 on the 20-sided die is a success. On an attack roll, it also threatens a critical hit. In contrast, a 1 is a failure on an attack or saving throw, but a variant rule that was introduced is to have a 1 be some kind of worse penalty than a simple miss. A lot of people think it penalizes attacks too much, but we've always used them (I blame John, though I kept the practice as DM). And at the very least, I tell them to roll again just to see what they'll get--only if they fail again (or fail really badly again, i.e., another 1) does something unfortunate happen.
My argument for critical fumbles isn't based on fairness, exactly. But just as an awesome critical hit that saved everyone is memorable, so too are the critical fumbles I've witnessed memorable. A great one came from a campaign John DMed, when our half-orc barbarian attempted to grab a villainous soldier in his office. Three ones later, he crashed out the window and was clinging to the sill, while I (the cleric again) and our ranger had to battle the guy and his minions. In our campaign last semester, fire elementals had bottled the group into a mineshaft, making them climb up to try to attack. They'd already gotten the dwarf up, and the scout was making his way up behind, hoping to shoot arrows at the creatures. When he got to the top, he rolled 5 ones within 6 rolls. On the last one, he shook his head, looked at me, and asked if he could just take one for the team. Instead of fumbling and firing into the dwarf, he fell down the shaft.
Strip 28 - Foresight and Cunning

"Taking 20" is what a character can do when no penalties for failure exist and they can keep trying until they do a task as well as they're going to do it. But by the rules, it takes 20 times as long, as it represents the idea of you rolling every number on the 20-sider over 20 rolls. Strength checks are actually a good thing to take 20 on, as are Search checks. If your character can possibly break it or find it, he or she will.
Strip 29 - Dice Karma

I don't know if it'd do any extra damage, but that flaming sword looks cool. Apparently the GM has a habit of reusing maps in his or her campaigns, which is at least efficient.
And don't laugh at your teammates who roll poorly, either--it'll be your turn eventually.
Strip 30 - I really don't see what the big deal about grappling is.
For someone else's take on this subject, see the comic here: http://www.darthsanddroids.net/episodes/0232.html
as well as the follow-up on the next page:
http://www.darthsanddroids.net/episodes/0233.html.
Shamus Young also considered doing a comic on this subject, but he decided to target Attacks of Opportunity instead (http://www.shamusyoung.com/twentysidedtale/?p=792, see also the annotation for this strip: http://www.shamusyoung.com/twentysidedtale/?p=691).
Now, I'm going to skewer the sacred cow of
complaining about grapple rules, but I find them sensibly written, although Step 4: Maintain the Grapple sounds kind of silly as an extra step. It seems the designers of 3.5's grappling actually thought through almost everything you could want to do while wrestling with an opponent. And they even formatted the grapple actions with their own boldface headings. Granted, grappling becomes messier when you don't have two humanoids facing off, but monster entries
always have their grapple modifiers listed, as do character sheets. Hopefully a player who wants to grapple or grapples frequently will also be kind enough to turn to the section in the handbook to help out the GM.
No, what really annoys me is the less well-written Trip and Disarm rules. They're almost identical to each other in concept, and most weapons that can disarm can also trip. They both involve opposed attack rolls with bonuses based on size categories. If you fail one, your opponent gets a free trip or disarm attempt (whichever you tried) against you. And if you use a weapon, you can drop the weapon to avoid the counter. But not all tripping weapons can disarm--see sickle-shaped bladed weapons--and most disarming weapons get some kind of bonus on disarms but not trips. Also, disarming takes penalties or gives bonuses based on the size of the weapon(s) involved. They're just similar enough to make it confusing to figure out the exact modifiers on whichever one you're trying at a given moment. Also, the Improved Trip feat is much better than Improved Disarm, considering it gives you a free attack on the prone opponent if you succeed on the trip. Pathfinder avoids this by lumping them all into a "Combat Maneuver" category, from what I've heard.
Bonus points for nerds: without looking at the SRD or a handbook, which attack can avoid attacks of opportunity if you use a melee weapon instead of your hands? Trip or disarm? This is another dissimilarity between the two.
All images used are owned by Disney, which does not endorse this parody.