Well, er.
RPG Maker doesn't have much gameplay of its own. The idea is to make -your- gameplay, for others to enjoy. It
does come with a highly enjoyable little adventure called
Gobli, which is basically a role-reversal of every other RPG ever made. Entertaining, but rather short and really just an example on how to do various things with the engine,
Gobli is really just icing on the cake.
RPG Maker consists of two major segments -- RPG Maker and Anime Maker. Most will spend all of their time in RPG Maker, as Anime Maker basically requires the use of a PS Mouse and is still a pain in the butt to deal with. Yes, you can do touch-ups and whatnot on the various sprites, but you're better off using the ones built-in to the system.
RPG Maker itself has two major modes as well. There's Data Edit, which lets you set up things like your character's abilities, the spells, skills, levels, monsters, and dungeons. And there's Scenario Edit, which is where you add all the scripting functionality that makes an RPG an RPG. Both are essential to make a full game, and both need to be understood fully before you dive into making the next epic.
Data Editing is where you do most of the nitty-gritty things. You create all the main characters in the game -- their looks, their statistics, what skills they can gain. You create the skills as well, along with spells. Spells can belong to up to three different families, if you want to differentiate them (Black, White, and Gray perhaps). You can also create your own creatures, using the 100 different pictures that come with RPG Maker or using those that you make in Anime Maker. Each creature has four distinct palettes, so you can turn that Pegasus into a Satanasus like I so enjoyed doing. Heh.
Another very important part of this mode is making the Dungeons. Everything is a Dungeon, from towns to temples to, well, dungeons. You place each tile on a map, creating where the player can and cannot go. It's actually quite simple, and with the AutoFix mode on (by default), it keeps you from having to choose the 'right' wall segments and things of that nature. They just build correctly auto-magically. If you want to have some weird construction, of course, you can do that as well. It seems daunting at first, but after messing around with it for a bit, the Dungeon Edit function is quite simple.
The Scenario Edit mode is very important as well. You place Events in the Dungeons, from treasure chests to wandering townspeople to automatically triggered events. This is all done by a series of commands, which form a rather chewy little RPG scripting dialect. It reminded me of the old ZZT and Megazeux scripting methods, in function if not in form. You can set flags as you desire, so you can have an event trigger later events and have diverging plotlines and whatever else floats your fancy.
There are some neat features not normally found in RPG’s, as well. You can have different scenarios that use the same data, letting you create episodic RPG’s, somewhat like the old Gold Box series. And the ability to playtest the game while cheating like a dog is very cool. It's always entertaining to walk around whilst invincible, wailing on all the bosses. Heh.