I have played this and it felt just like the original. However, if I recall correctly, one needs to own the original install file of RCT2 to install OpenRCT2.
For best results, you should have the full game of RCT1 (Deluxe) and RCT2 (Triple Thrill Pack). Both can be bought on GOG or Steam, frequently on sale.
For a still-functional-but-not-ideal experience, you can get started with the RCT2 demo, or with RCT Classic. But again, above is recommended.