The 'melting' mechanic is unique and made for some fun challenges. The character moves at a snail's pace though so you pretty much have to hold the run button the whole time, why not just up the players movement and get rid of that entirely? A little tutorial text can go a long way here, like "WASD" to move.. etc. I pressed every button on my keyboard at game start only to read the description and realize I needed to click the door to start. The secret ending was cool but it was hard to tell if it was a bug, adding text in that section would help for this as well. Solid work.