Honestly, this could definitely use a lot of improvement. The jump button doesn't seem to work half of the time, the level design and transitions from level to level are confusing, and the AI is underwhelming at best. I do think it's pretty neat that the character gets higher and higher if you hold the jump arrow key down long enough.
Personally, simply fixing the controls and making the camera follow the player's position would probably be the first stepping stone in to making this a better game. Some better transitions between levels would also help the game out as well.
Overall, this definitely needs improvement imo.