I was required to design a board game themed around connection and could only use two gameplay elements besides the board and player pieces.
My immediate thought was physical connection. However, I kept running into the same problem with this coop idea: if the goal was simply to get the two players to reach one another, then there was no challenge.
So I decided to flip it on its head by making it a competitive game where connection needs to be achieved and avoided. One needs to approach their opponent, but puts themself at risk as well.
I found that my testers didn't fully understand the game until they were already playing it, however they learned through play quickly. It could also speak to the simplicity of control. You can only either move your pawn or place bridges, and you have to get used to building out your bridges and thus seeing all the different tiles you have at your disposal before you can reach and enter combat with your opponent.
When they were confident about the rules, they played well and were able to strategize thoughtfully. When they were unsure about a rule however, the game came to a screeching halt. With this, I understood that not only is it better to make all rules clear to prevent the game from falling apart, it's also better to make the game's framework strict and rigid.
Read the game's rule book, as well as my musings on how the game turned out at the time.
Photos I took during playtesting, two of which are used above.