' It is so lame to have 20 rounds that are strong against X but weak against Y, and then to have round 21 be strong against Y and weak against X.'
no it adds difficulty, stop complaining because you can't do it.
'To me, that is just poor level design, not “deep strategy” as this game is tagged.'
it's great field design, it's very diverse.
The only thing I don't like about this version of defender is that they don't upgrade as they go up the levels like they did in defender. Apart from that I love it.
 "Pillage the Village")
 "Line Snafu")
 "ZunderFury")
 "Line Game"){kind=icon}
 "Gravitee")
 "Treasure Seas Inc")
 "Game Extravaganza")
 "Dragon Run"){kind=icon}
 "Click Breakout - The Test")
 "Protector")
 "Roll")
 "Coil")
 "Shape-a-licious")
 "Kermix"){kind=icon}
 "The Unfair Platformer"){kind=icon}
 "Ring Pass Not")