A cool concept with some interesting puzzles but I think there's a lot of room for improvement. Firstly, I would have made the window that you play the game in much bigger. I found it a bit frustrating to have to focus so much on a small window especially when the screen is very zoomed out for bigger levels. I also had some trouble with the movement. It was difficult for me to fit one of the characters in between a wall and the lava as there is no room for error. To solve this, I would suggest making the player characters smaller so they don't get stuck between walls and lava so easily and that there is a bit more room for error. You could have also limited movement to a grid to make things more precise and strategic. Lastly, I found that having one of the players stop when the reach the flag made getting the second player to the flag too easy. It would have been a fun challenge to have to get both players to the flag together. All in all, I think this is a really cool concept that fit the theme very well, and I hope that you expand it and work out some of the issues in another game or update because that's definitely something I'd want to play. Good job!