Controlling the characters (horse, chicken, sheep and a few others) is relatively easy, because they can only jump and bounce off the walls.
You do not receive points for completing such levels, so for the fun to make sense, we have to add the rest of the objects ourselves. However, if someone dies, the game adds bonuses for reaching the finish line in the first place, for placing a trap that someone has fallen into, for collecting coins, etc. To receive points for completing a level, the basic condition must be met - at least one player must die during the race.