Interestingly, Rollercoaster World has the best rollercoaster design tools I've ever seen. Its also a terrible game.
The gameplay is split into three different areas of park management. The first is the buying screen where you, well buy stuff. This includes rides, stalls, scenery, advertising and coaster upgrades. The interface is boring, the models look unacceptably atrocious and the options for customising objects is limited to 'this is it, tak it or leave it'.
Secondly, the first person perspective is the least involving and worst looking of the lot. you walk round in a 3D environment with 2D character models which look as if they were ripped straight from 'Duke Nukem: PowerPoint Edition'. But seriously, the character models wouldn't even be acceptable 10 years before the game was released. The pictures used for the for the these models were clearly too small to start with and were obviously increased in size meaning every pixel is approximately a square foot in size. In the first person perspective, you can also buy from the shops you built. Why any park manager would have to pay for a crepe from their own shop is beyond me. What's more infuriating is upon eating the crepe you don't get any bonuses like increased efficiency, you simply get a pop up message saying some stale line among the likes of "Mmm, that was nice". Really, if the game must use the pop up tactic, it could have at least used interesting text. How about "I'm a vegetarian! Please stop making me eat these cheese burgers" or "Has someone wanked in this ice cream?". The only useful upgrades are the running shoes and jetpack, only beacuse they increase the speed your hideously slow character, who has the movement speed of a cat with no legs who's learnt to drag itself by its tongue. The building models look even worse under the close scrutiny of the first person mode, they mainly consist of a square-with-another-square-on-top or a square-with-an-oh-so-adventurous circle-on-top. Theres really a lot left to be desired in the graphics department.
Finally, the last and best area of management is the rollercoaster design itself. I would actually reccommend this game to you just for the 'coaster design tools. But only if you REALLY liked rollercoasters. Like, had a shrine in your wardrobe with pictures of 'Oblivion' in. The design tools are great. They simply give you a three-dimensional grid and say "Wahey! Go mental! There are no rules!" What inevitably happens is, like a child in a sweet shop, you go mental. "Woo! I'm going to make this one go really high and then plummet to the floor and turn really sharply so all the passengers get flung out like a kid with aspergers operating a tennis ball machine!" Also cool is the colour options, which allow you to make each rail any colour, including transparent. Its awesome to see the carriage flying about on seemingly nothing.
In all, rollercoaster world is a game that fails where so many other theme park simulators achieve. And, while the 'coaster editor is great, its not enough to save the game from being a ugly mess.