no, you will have the ability to download the new versions when available.
Viewing post in The Villain Sim Beta 43 now on Itch.io comments
upper right menu option, then go to “My Library”. You will see the game there. Select it and then read through the page until you see the latest version available, then download and install it.
I messed up and purchased it twice not realizing I could do it. A new version came out a very short time after my first purchase. Oh well. I just considered it a donation.