Zombies Ate My Neighbors and Ghoul Patrol (UP)

On Level 10: No assembly required there is an area where the chucky dolls will spawn infinitely and they cant touch you (location in video). Stand here and throw soda cans over at them, for the most effectiveness wait until the maximum of them has spawned (5). Sometimes a fire version spawns after you kill one these are worth even more points. Each soda can can get you about 1,000 points

I opted to do this an easier (but much more tedious) way.
If you load up the first level of Ghoul Patrol, go down and then left, pick up the key at the end of the hall, then go back to the right and unlock the door below you, there’s a ring of eyeballs that spawn indefinitely - you can constantly shoot these for points until you reach 250,000.
Also, if you complete the rest of the level and pick up the potions that turn you into a grim reaper, I think you get more points per enemy, same goes with other weapons, so if you use up all your ammo and potions first, (this got me to about 90,000) then just shoot your crossbow after this getting a whopping 20 points per kill.

See the video below: