There are more monsters in total. The number of monsters on screen at once increases. The number of times nobbins have to cross to become hobbins decreases. Hobbins stay hobbins for longer. Gold hangs around for less long.
Fire takes longer to recharge.
Bonus mode lasts for less long. Levels above 10 use the same variables as level 10 but different layouts. Monsters going up change direction when there is a bag falling on them, but they do the same thing even if the bag is below them in the same column. The noise made when you complete a level is polyphonic if no background music has been played since the game was started. The program allocates enough resources for 6 monsters, but only 5 are on screen at any given time.