Character creation
Compared to WoW or FFXI, the character system is quite simple. Your 'toon is a human wizard, with customization options limited to gender, hair color and facial features (which other players usually can't see in much detail anyway), and a selection of kid-safe name elements. You do get to pick the color and trim of your character's starting clothes (hat, robe and boots), but you will very quickly loot and buy equipment upgrades that throw the whole fashion-plate concept off, so don't get too attached.
The one meaningful initial character differention is your choice of magic speciality: fire, ice, myth, balance, storm, necromancy, life, etc. Spells unlocked in your school by level are free; spells from other schools may be bought with skill points doled out every 4-5 levels.
Gameplay
Combat is turn-based, and patterned on Magic: the Gathering, Pokemon, and their zillion derivatives: your spells are represented by "cards" in a "deck", a "hand" of which are randomly dealt at the start of a combat, and another spell-card is drawn from your deck each time you successfully cast. Players and computer-controlled adversaries choose their spells, and then the computer resolves their casting choices in some sort of order until everyone has cast (or fizzled) their spells.
Your goal is to cast spells that inflict damage, reducing your opponent's hitpoints to zero, while conserving your own hitpoints. Most spells also have a mana point cost. When you're out of hitpoints ("killed"), you're teleported back to town. When you're out of mana points, you need to find "wisps" that spawn and wander regularly around town or more rarely in the monster-populated areas, or play minigames at the fairground, to refill your mana point reserve.
Gear will expand and modify your basic spell options; for example, a necromancer specialist starts with a wand that automatically adds a handful of minor life-drain spells to their deck. Gear can also modify your max hitpoint and mana point reserves, spell power, and spell resistance.
Character development
Predictably, as you defeat opponents and finish quests, you get experience points and level up your character. Gaining levels unlocks more powerful spells, skill points to buy spells from other schools, and gear.
Midgame and economy
Representing castable spells as cards results in two distinctive game mechanics: higher-power spells as consumable items, and crafting as a means to producing them for consumption. The pinnacle of crafting in Wizard101 is production of "treasure cards" (consumable spells) and enchantments that further boost their power.
The great bulk of the crafting-to-consumable endgame cycle is not possible under the free-to-play limitations, because the recipes must be purchased with cash-equivalent tokens, and ingredients for the high-demand recipes are in paid-expansion areas. This means free-players are confined to lowbie areas and can never approach PvP on even footing with paying players.
the environment
Some of these craft ingredients are purchased from vendors. Others must be found around the world. The crafting starter quest called for some cattails, and in my first craft-harvesting run out of the gate, another overzealous player reported me out of the blue for grabbing a cattail spawn point or random cashbox. Yes, small amounts of gold coin periodically pop up out of nowhere in certain places, but it's probably more lucrative to grind on monsters. Suffice it say though, fishing/harvesting drama is not dead even in a kid game like Wizard101.
Most of the creatures, and the surfaces and buildings of the world itself, have a distinctly cartoony feel, somewhat reminiscent of Kingdom Hearts. Somebody did their psych research - for a story themed on the threat of an undead invasion, the undead are sufficiently non-scary that even sensitive preteens should be desensitized quickly. The skeleton are all pirates, the zombies and ghouls wear top-hats, the ghosts are more Haunted Mansion, not LotR.
The scenery and vistas are interesting, but your limited up-down range of visual motion ensures you won't be awestruck for long. This also makes it difficult to appreciate the intricate 3D modeling of your fellow players and their pets. Despite the huge visual variety, the most dramatically eyecatching aspect of the game as an onlooker is the repetitious spellcasting.
A lot of finesse went into the spell animations, as expected in a game where spellcasting is so center-stage. Ultimately though, waiting for each 5-10 second animation is a drag.
The world itself is divided into distinct zones at various gates and doorways. The starter areas, "Wizard City", are styled as a busy medieval-fantasy town, with monster-ridden-encounter areas in separate zones around its fringes. Within the free-to-play limitations there are no real "wilderness" or "dungeon" areas - even at the far reaches, there are sidewalks which monsters politely avoid. Some of these zones are sinister-looking and kiddie-horror-themed, yet still well-lit - no eye-strain-y atmospheres.
verdict
Wizard101 has two major strikes against it: first, it is is "kiddie" enough that anyone who was old enough to find it appealing when it came out 5 years ago, has by now outgrown it and is ready for more complex MMORPGs of the ilk of WoW, FFXI/V, Tera, or LoTRO. Second, unlike LoTRO which can be unlocked entirely for free with some patience, Wizard101 is not truly "free to play". It is free to try, but unless you're happy to retire to pointless grinding in lowbie areas or running new characters through the starter quest sequence, there is just nothing much to do after a long Saturday's immersion.