I agree about the sizing Dee, it's a little too big for my larger (27 inch) screen. I imagine it's to do with the mitigations that Gary put in place for the previous version of Adventuron not being required any more, but I'm open minded that it's still a bug in Adventuron too.
As far as the gate not opening at the start, I just tried it and it seems to work fine for me.
Dee - Can you restart the game and try it again? (type QUIT to restart)