The itch.io site says "Tuesday" but the og:description says "2020-03-09".

When does it end?

Whatever the itch.io page says is when it ends. For me it says:

Submissions open from Tomorrow at 12:00 AM to Tuesday at 12:00 AM

Depending on your time zone it ends on a monday/tuesday.

Then there is a 3 weeks voting period. Which is what appears on the link metadata, and may be confusing you

Ok thank you both