First of all, bear in mind that my low steam playtime is just that. I used to beat the crap out of the game disc on my first laptop, so you can easily add 80 hours to the playtime.
Well, RollerCoaster Tycoon 3 is now an aging beast. The game originally released in 2004, and that unfortunally shows. While graphics isn't the main or even secondary reason you would like to play this game, there are some now hard to forgive kinks in that department like the lack of native 1080p support. There are of course workarounds to this, but then again, it's hard to blame a game from before widescreens became common to have widescreen support.
So, what about the game itself? Well, it's really as solid as you would expect the sequel to RCT2 would be. While the iconic, isometric pixel art of the first two games have been replaced with 3D, it really looks good for its age. There is content enough in the game to keep you sucked in for a long, long time, plenty of RollerCoaster types and designs to keep you interested and best of all, the people in the park aren't as timid as they were in the first two games, allowing you to build more extreme rides without it having a negative impact on your play.
So, why would you buy this? Honestly, Nostalgia is the main reason. But it does this very, very well and I still return to it ten years later.