That was close, I almost didn't make it to the portal after collecting the coins. Nice little game! I think my sound broke though as it just suddenly stopped working.
One potential issue I can see is getting a really low number on the dice roll and it becomes impossible to complete a run. That wouldn't really be fair to the player.
I think some sort of upgrade system and progression system after entering the portal instead of just "you won" could add a lot of extra replay value to the game if you want to make updates to it :)