The large bounding box really ruins the game

While jumping you bounce into objects that are >16px away.
If you mean the platforms, then there's not much I can do without breaking the levels.
(Not enough time now for a rewrite).
If you mean the objects, then the collision detection could be better, as it's based on the sprite size which are multiples of 16 and square.
In particular the bounding box for the ladybird is a poor fit vertically. I'll take another look at this, but struggling for bytes now.
Edit: I did a trial build with variable sized sprites. Problem now is you don't get enough bounce off the ladybird to get to the platform. Also I've added too much code. Probably best to redesign the ladybird sprite to fill the 64x64 sprite and leave the code alone. Ho Hum.
Edit 2: I've shrunk the object bounding boxes and fixed the bounce off the back of the ladybird. Definitely an improvement

However the codebase is now over 4k, so needs some optimisation or something taken out. That'll have to wait for friday.