My sprite falls through the floor
You press Play and the hero drops straight through the ground and off the bottom of the level.
Check these first
- Is the floor solid? Click the floor. In the Properties panel, Is it solid? must be Solid (blocks everything) or Platform (jump up through it). Just decoration stops nothing.
- Is the floor a sprite? Sprites are never solid. The floor must be a Block, a tile from the library, or a background. Delete the sprite floor and add Grass from + Add object โ Library.
- Is the floor on a hidden layer? In the Layers panel, a layer with โ is hidden. Hidden layers are left out of the game. Click it to show the layer.
- Is the hero already inside the floor? A sprite that starts overlapping the floor can slip through. Nudge it up with the arrow keys until it sits on top.
- Is gravity very strong? A high Gravity strength can push a fast faller through a thin floor. Make the floor thicker, or turn the slider down.
- Is there a gap? Tick Snap to grid and look along the floor for a missing tile.

Why it happens
NutHouse only treats tiles, Blocks and backgrounds as ground, and only when their Is it solid? setting says so. A sprite with a picture of grass is still a sprite, so the hero passes through it. Hidden layers are left out of the game entirely, so a floor on a hidden layer is the same as no floor.