Yeah, apparently mine was still on v0.4.12. Luckily I can use bylectra's method. It's strange that both the v0.4.18 and v0.4.19 are still compressed after updating the game through itch.io. Rather than replacing the file, both files just exists side by side.
Edit: Forgot to mention I can only play the latest update in the browser despite extrating the file. Currently the downloaded version is still on v0.4.12. The itch.io app still says it's already updated to the latest version.