Hello from Humble Bundle :)

I've always wanted to own this software, and now I can. Started my game last night, it's gonna be awesome. 

Any one know how I can add a "Giant Mech" to the world screen? Like an oversize sprite.

Welcome to the world of RPG Maker.

I recommend you check out the basic tutorials before you begin, they will help set the foundations on what you can do. It's best not to overcomplicate things at first so I also advise you to try condensing your first project into a smaller, achieveable size. This will allow you to have the knowledge you need for your bigger ambitions. It seems like you have a lot in mind on what you do, but this might end up disappointing you in the long run.

I would like to help give you advice on adding that giant mech of yours, but I'm a bit confused to what you specifically want. Do you wish to add your own picture to a map? Do you wish to add your own customised sprites to your map? Do you wish to change the title screen?

There are plenty of resources out there which probably include those beloved giant mechs of yours. I'd go for a google if I were you, then follow their instructions on how to import them in the game (if that's what you wanted.) Don't forget to give credit to whoever supplied you your mech.

Welcome to the group! ^_^

As to using a large sprite, don't go too large or you'll have problems, but anyway...Placing a $ before the rest of the file name will tell RPGMaker that the spritesheet is 3 characters wide, by 4 characters high which is the "size" for a sheet with only a single 4-direction animated sprite, or 4 single direction animated sprites. Make sure the image size's height is precisely divisible by 4 and its width by 3.

If you go into the engine's "RTP" folder > "Graphics" folder > "Characters" folder you can see how it is done using the "BigMonster" files. These would be used like your "Giant Mech".

Welcome aboard Solace. Just a tip, don't get too addicted to this.