I was playing the web version, and even I was holding the down button, the gate animation plays but it won't let me through.
Viewing post in Professor McLoop's Time Tangle jam comments
Sorry about that! We'll hopefully get it fixed soon in a future update.
In the meantime a workaround solution is to turn your monitors refresh rate down. To do this:
Navigate to your pc's display settings menu
Find where it says refresh rate (might be in advanced options)
Lower it (lower than 60Hz should do it) and press keep changes
Remember to change it back after your done playing!
Hope this helps and thank you for your feedback :)