https://www.newgrounds.com/portal/view/626809?emulate=flash Trying it out on the current build on NG, the preloader on the right seems to finish up fully and shows a playable button, but clicking on it does absolutely nothing, same for the "click here to play" text on top. Meanwhile the loading percent on the left does not change at all.
The loading percentage on the Jack O Lantern should be going up instead of being stuck at 0% and you should be able to start the game.
Update with the latest nightly, the desktop build as well as certain other sites hosting this game like https://kbhgames.com/game/freak-o-lantern have no issue with the preloader now, actually letting you get to the title screen and ingame.
The version of the game hosted on Newgrounds though still seems to have an issue with this preloader, seeing this error from the console log. However, you can use the right click and play method to get in game now after around 10-15 seconds of waiting. (Wait for white text to show up behind the middle of the preloader on the bottom right then disappear after a few seconds, then it is safe to right click and play)
Error occured when running AVM2 frame script: RustError("Cannot access property ::addEventListener of null or undefined")
Re-testing on NG again, it seems like the game doesn't have issues loading up anymore, it's a little slow when loading, but it's capable of getting ingame now.