Thank you for your interest and for letting us know about this! This was a 6 week project, so the game is still work-in-progress and definitely far from being bug free. Here are some workarounds that can help you get unstuck: (1) please refresh the itch.io page to restart the game instead of using the main menu to restart, (2) After blasting the rocks in room 1, please go and collect the second card in the chest to unlock the second room, (3) Dummy1_R is unfortunately very punishing so you would have to apply both the buff and debuff in the overworld to one-shot it in one turn.
Hope this helps!