Day 12 - HELP!

[rubyslippers88]

I need some tips for Day 12.  Any suggestions?

[pixlepix]

After getting crystals and making a reactor base, go for the big chamber to the right. Once that is defeated, dig a hole down through the bottom. Then, go for the gateway. Save your Greeper for this, this is the important fight. If some tunnels break out, hold them off with shields/repulsers. Then, just mop up the emitters easily.

[pecet]

I killed all creeper in this level, but level isn't finished, what to do now?
edit: ok, thanks guys from chat, i used nullifer on gateway

[MadMag]

Take out the drone gate between your launchers with a nullifier.