Having issues with construct 2 and collisions

i am starting a platformer, and for some reason i am having issues with the player (16x16px) going through a gap (16x16px) under a tile that is 16x16.

I havent messed around with the collision boxes. but i thought it could be the problem, so i started fresh and again, the player can't get past the gap under the tile..

If you run your project in debug mode, you can notice that the character Y coordinate is not exactly at the floor level, but a fraction of a pixel above it. It's how Platform behavior works.

So you need to move the top tile a few pixels up, or decrease the height of the collision polygon on character sprite.

It's also worth noting that "touching" counts as a collision ( distance of 0 ). So if you have a 16x16 character moving on a 16x16 grid they will not be able to move through 1 tile spaces. If you reduce your collision rect by a fraction of a pixel the issue will go away.

nice. thank you both for your replies.