you are right. but then the zombies should have more 'intelligence' - i had more intelligence - but then it was even more hard. i think if you try it more often you learn to live with their jumping around. in fact they are not so bad as they look like .-)
i managed to make 2500 pts .-) but i played it also a lot for testing. that was playing 2.5 areas.
but perhaps if i have the time to make a version with more bytes. more balance would be cool. there was also one version, where you could instead of money get some new assets to use. and the game was on time. of course there should be more decisons and more crafting. but for this i had to start again with the concept. next time.