Only 4

Levels 12,13,14,15 are the 4 patterns that repeat so having 1 strategy for each would work for a while until the enemies become too fast

patience = more points I think the most you can get is 800 points for pumping up Pooka's at the lowest level and 1000 for Frygars. So 1000-2000 points max potentially for the last 2 enemies if you want to blast through levels quick. But you won't always get two Frygars at the end of a levels/pump them both up at the bottom for 1k each. A rock drop on the last two enemies is 2500 points so that's why I go for it each level. That extra 500 points adds up across 240+ levels when you are trying to max out score per level/get a WR caliber score at the kill screen. But the reality is that you also might just pump out the last two Pookas at the top for just 200 points each, so that would be just 400 points vs 2500 on those levels. I agree that it is a big drag to have to waste time grouping up the last two enemies every level from around 12+. But that's the price you have to pay for high scores ;)

We had the console at the local swimming pool when I was a child. The toast button and controls were all sticky and weakened. I recall 10p per game