Your health will keep decreasing, so keep hitting enemies to get
additional health packs. Destroy things that regenerate enemies,
specially the scorpions <#> and purple sludges. Run away from the purple
sludges while you shoot the Boss Core. Keep at least one regenerator so
the Boss <#> cannot summon more of them. If you have a bomb, use it
while having the homing/spread weapon equipped. Stay away from enemies,
and keep a high-level weapon at all times.