The "EnemyWave" objects had their animations *severely* trimmed down from the originals, as they were extremely long otherwise (almost a thousand frames!) for what is essentially a looping animation scrolling across the screen. Here are the animation speeds of each:

EnemyWave10 = 1 pixel every two frames, cycle resets every 10th frame (101010101, repeat).
EnemyWave20 = 1 pixel every frame, two pixels every four frames (2111, repeat).
EnemyWave30 = 1 pixel every frame, skip every 5th frame (11110, repeat), erroneously resets every 500 frames.
EnemyWave45 = 1 pixel every frame, two pixels every four frames, cycle resets every 12th frame (21112111211, repeat).
EnemyWave60 = 1 pixel then 2 pixels twice (122, repeat), erroneously resets every 333 frames.