Ooh I loved this one! It's simplistic but does everything competently enough to make the player plan their turns carefully. Here's some stuff I think would improve it.
1. A "Pass All" button that makes all your heroes pass so you don't have to click them individually.
2. Sound effects for anything and everything. It really does help.
3. Stopping the player from selecting heroes during animations so they can't break it even if they wanted to, and/or letting the player skip animations by clicking if they want to.
4. Add an indicator for when the thief is able to do backstabs and show the range that other enemies have to be at for a backstab to be possible. It felt inconsistent so I didn't know exactly how that mechanic worked.
And you're a first-time jammer? You newbies have been knocking these out of the park, and this is no exception.