An Eye boss known as Guardian Eye, the boss from fourth level. This boss is a big eye followed with smaller eyes, but for alpha stage we used only the big eye phase. At first we designed the bosses for one health bar, but because the player ship could dish too much damage with bombs and stop time, one shooting the bosses. We decided to implement bosses with many health bars, one per a set of patterns and you couldn’t damage the boss between health bars. With this change the player could skip only one or two patterns. We could nerf the player “power levels”, but we don’t like this approach.
Another important point from bosses is they are timed, when the timer ends, they run. This is to prevent boss milking and prize the players who kills the boss faster.