You can ride them in 3...but overall gameplay in 3 is just...different then 1 and 2. I don't like 3.
I like 2 better, because you can actually theme rides well (you can't stack scenery in 1), and when scenery is in the way, it automatically destroys it when you build something, instead of having to right click each item in 1.
You can also make your own scenarios, you can save track designs, there's just more.
However, some things they made too complicated and expanded in 2. In RCT1, the "Boat hire" contained all the boats in one, Bumper boats, rowing boats, swans, etc. In rct2 however, they're all listed as different rides.
Both are awesome, but I find 2 overall more fun.
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I've added a Space themed area, when I add more to the park overall, I'll probably post an update picture.
If anyone wants to see a specific area up close, feel free to ask.