Slamt4stic thx

@Slamt4stic Your method works. Thanks.

@Destroi Old post but worth a reply:

You can change the target exe file for any steam game under the desired game's properties menu (right click on the game in steam library). Once in properties look for "launch options" and there should be a line for inputting your own commands.

In this line you wan to put the full file path to the openrct2 exe file inside of quotations followed by a single space and %command%

For me the launch options looks like:

"C:\Program Files (x86)\OpenRCT2\openrct2.exe" %command%

This should launch the desired exe file with the steam overlay, hours tracked, etc.

This same trick also works with Morrowind when using OpenMW, Daggerfall with Daggerfall Unity, Terraria with the mod loader, etc. etc.

You can try making the file read only for a start. Don't have the time to test it myself.

This worked before the lastest update. Now however, the original RCT.exe just gets copied and it runs instead of the openrct2, even after renaming the original and the openrct2 application.

any ideas?

It works!!!!!!

Finally a guide that works! Big ups!

works, tyvm

For me Steam still starts the OpenRCT I downloaded in 2016, and doesn't redownload the exe or anything.
Modern games like Horizon Zero Dawn also let me replace the exe with my own with no issues.

Not working. I followed the guide but when I hit play in Steam it just re-downloads the original executable and launch the original version.