Heroes & Other WorldsAfter more time reading, I've come to appreciate that the two classes have a lot of depth in terms of options. You can create uber-powerful one-trick ponies (who will quickly burn through EN in the case of wizards) or weaker/average characters with more versatile repertoires. Fortunately, both versions seem equally viable.
The Adventuring section is dungeoneering 101 with some rules on poison, fire, secret doors, light, and wandering monsters. Some noteworthy advice is that an addition to a Mapper (who makes maps) the party should have a "Caller," a sort of spokesperson for the group to the GM.
When it comes to combat, HOW is crunchier than homemade fried chicken coated with cornflakes. Unlike in D&D (mainly speaking from a 3.x perspective here) were movement can be done willy-nilly unless you're capable of multiple attacks, HOW's combat is much more cerebral. To cast a spell or shoot a ranged weapon, the farthest you can move is 1 space (5 feet). To be able to defend/react to an attack you have to move half your Movement (MV) value or less and you can't move the next turn. The questions of when to move, how far to move, whether to defend, and how to defend (dodge, parry, block) make combat very engaging. It should be noted that although Brandon mentions both hex and square grids in the introduction, HOW is very clearly designed to operate on hex maps. Facing is mentioned, especially in relation to shields and sneak attacks, but not elaborated upon. I'm assuming that your facing will be whatever direction you last moved in or toward the location of your most recent attack targets.
The default Experience Point system is pretty simple: Characters receive 3 XP for each test successfully passed, with bonus XP if it was an extremely difficult (i.e. a test where you have to roll under a target number using 4D6 or 5D6). The only concern I can think of is munchkins trying to make a bajillion Detect Hidden (equivalent to D&D 3.5's Spot) and/or Detect Lies (equivalent to Sense Motive) in order to rack up XP faster. A strong GM hand will probably curtail that crap should it come up in-game.
The Referee Resources section is very short, giving pointers on how to improvise for player's crazy stunts and advancing a Gygaxian philosophy of creating atmosphere using non-visual phenomena such as smell and taste. It also features a handy selection of NPCs and hirelings.
The treasure section covers all the typical doodads you've come to expect from traditional fantasy, with some appropriately designated "Oddities" thrown in for flavor. One thing to note from the treasure tables is that magic items are comparatively rare.
Following the magic items section is a small "Find your Fate"-style solo adventure that I'll play through at some future junction. Past this is a guide on constructing your own dungeons and adventures, including various random generators, NPC reaction tables, and a sample dungeon. One thing I don't like about this section is the very oldschool "Gotcha!" trapfinding method. Not only does a player have to say where his character is looking for traps, he has to say how that character is looking for traps. This has always felt to me like something easily abused by asshole GMs or that would drag on a game to the point of boredom as the party takes 30 minutes in real time to clear a average dungeon hallway. I'm not in favor of the D&D 3.5 "I roll to find traps" method either, but I've yet to find a good intermediary between what I consider two extremes.
The equipment sections features the ever-essential weapons and armor, miscellaneous tools, and "flavor" items like silk gloves and fancy gloves. The entire section is five pages of rules composed almost entirely of charts. An availability check rule helps determine what items can be found in certain regions. This section is lacking in some fundamental information for tools, like what caltrops actually do rules-wise or how many approximate pages you can write/draw using a single container of ink. These are pretty minor complaints though.
I stand by my earlier statement that Heroes & Other Worlds is a great little system.
Magi CartaMagi Carta can be divided into three distinct pieces: New rules; revised spells from the core rulebook; and spells converted from the D&D 3.5 SRD/OGL.
For the new rules, I've already opined on the Wizard Staffs and Familiar sections, so I'll focus on the other sections. The first thing here is optional limits to learning spells. For example, a country bumpkin wizard can't start the game knowing Chain Lightning (an IQ 14 spell); he's limited to IQ 8 or lower spells at the start of his career no matter how much of a supra-genius he may be. Another option is a sort of "spell tax" where you must learn low-level spells to learn high level spells. Under this system, in order to learn an IQ 11 spell, you need to have an IQ 10, IQ 9, and IQ 8 spell as well. If you want to learn two IQ 11 spells, you need two spells of each lesser IQ level. It feels too constraining for my tastes.
There's also Cartomancy, spells inscribed on cards that are thrown Gambit-style and can be activated by anyone for the low price of 2 EN. Unfortunately they're pretty difficult to make and for most wizards they'll end up being extra IQ 8 spells. Still, a neat concept.
Dermal Magic is magical scarification that doubles the potential spells a wizard can know. There's also magic tattoos for wizardly wusses which also expands a wizards spell capacity but makes casting the inscribed spells more difficult. By RAW it appears that only wizards can use dermal magic.
Next are Spell Gems, which are similar in concept to D&Desque wands (Magi Carta's staffs are more like GURPS' magic staves). They can either be used to cast a stored spell or thrown as magical grenades.
I already covered Wizard Staffs (and Familiars) but I want to say that despite the awkward composition of the Staff text, the rules seem very sound.
Wrapping up the new rules are Spellbooks. I am so very, very glad that Brandon didn't make Spellbooks Vancian-style items. A spellbook is like a magic scroll but permanent; you can use it to cast spells but the spells won't fade away. Spellbooks are also the only way to learn a spell that is above your IQ (wizards only. Sorry adventurers :< )
As for the old spells, most are relatively unchanged (Enfeeble, Magic Strike). The rest are either expanded/clarified (Drop, Iron Flesh) or nerfed (the Freeze spells, Summon [Spectral] Bear) compared to their core versions.
With regards to the OGL spells, Brandon very sensibly altered many of the effects so that Color Spray is very powerful but not quite as effective as it is in D&D 3.5 (unless you're fighting Goblins).
(Tasha's) Hideous Laughter has also been nerfed so that exploits such as hitting Demogorgon with Hideous Laughter and the unleashing a salvo of murder on him are unlikely. Problematic spells like Sleep are also split up into multiple spells with the weakest like Lesser Sleep only affecting one target.
Overall, I'd say Magi Carta is a really good add-on for players and GMs wanting more thematic magic in their games.