All that Ben Jos says is correct ; leeching is very hard to determinate in this game ; and Matt, sometimes it is necessary to stomp several times on enemies head because it makes them loosen the yellow thing they still carry and you have to pick without entrapping them to get 20000 pts bonus(posted 8420 days ago)During all the week I've played the game (I finally managed to finish all 30 originals levels :))), I changed my mind ; as Ben Jos, I refused to do the stomping leeching (even on round 23, which penalized me about 50000pts)
So I think the best way to fight this sort of leeching is try get the higher level you can ; I've finished level 30 with 1 life left, Ben Jos and Ryan finished it with 0 life left : even if you know the game , it's not so easy to made a "30 levels loop" without dying ; and IMO doing 9999999 (7 or 8 loops) would also be an exploit
So I think now it's better to keep scoring as it is (b) to avoid leeching effects. Or maybe we could think about another type of scoring which counts score after 30 levels AND number of life left (score after level 30 + 1000000xlifes left for example)