Understood. I was certainly hesitant about making this post in fear of backlash, but it seems that many of you have embraced it. Thanks for your interest!
Yes, the game is mission-based, but by the time you're at the end (anywhere from 10 to 30 hours, probably -- it totally depends on how much time and effort you put into building), you're given a park that gives you total freedom. Actually, you can finish the story, but the game is never really "over" until you decide to stop playing it.
Back of the box says 650KB. I hope that works for you.
There's a total of 101 attractions. From the fact sheet for the game: "Thrillville boasts the simplest, most intuitive development tools available for all 75-plus ride types, from wooden, corkscrew and inverted coasters to merry-go-rounds, trains and all your favorite carnival rides." The other 20-plus attractions are the minigames.
Honestly, I'm not familiar with RCT3 enough to make comparisons, so I'm not sure if it's more flexible. I can tell you that there are designated "build areas" within each park, and, for example, if there's a tree within the topogrophy but you want to put your ride there, the game will automatically move the tree.
Again, I can't give you a definitive answer on that (there's still quite a bit of this game for me to play myself), but I can tell you that, with an emphasis on fun versus realism, you can create some pretty wicked rides that defy the laws of physics.
Yes, I quite like visiting amusement parks and riding the rides within. I grew up in Houston and visited AstroWorld (may it rest in peace) about seven or eight times, though it wasn't until the last few of those that I finally overcame my fear of the Texas Cyclone. I've also been to Six Flags Over Texas in Dallas, Libertyland in Memphis (which I believe is also closed now), Six Flags Great America in Chicago, Disneyworld (including Epcot, MGM, etc.), Disneyland, both Universal Studios, Islands of Adventure, Fiesta Texas in San Antonio... that might be it, though I may have forgotten one or two. One of these days I'll make it to the parks out here in the Bay Area. Anyway... Thanks for asking.