DescentBB

I've come back to this campaign after over a year hiatus and I've forgotten how to solve level 4. I've acquired the yellow and blue keys, destroyed two sub reactors. Lost my way to the secret portal and haven't opened up the wall leading to the area with the red key. What do I do now?

I barely remember it either, but from what I do recall there should be a door that opens near the guide-bot enclosure after the reactor blows. Blasting this (EDIT: the trigger behind it) will open the way to the red key, I think.

I'll play through the level in an hour or two so I can give you a more definite answer...

If you haven't killed the reactor yet, you need to do so in order to complete the level. Typically the blue and red keys are gained while the reactor is in countdown (that's why there are so many mini-reactors).

oh, this is gonna suck! lol

It is. For some reason the level is more difficult than I thought I made it, but blowing mini-reactors will give you more time.

The first one you should blow is obvious. After you're done with that, make your way to the exit and kill the mini-reactor/blow the trigger there, if you haven't done so already.

Then head to the circular hallway, and find the new door off that. Head in there, blow the mini-reactor and the trigger behind it, and you'll have the blue key. (Though it sounds like you've already done this as well.)

Following that, head to the blue door, go in there and wreck the last mini-reactor... the trigger behind that unlocks the exit. Note that you'll still need to open the exit door - it doesn't automatically open.

The haul from this level should be pretty decent by the time you're done with it though. It's not too tough if you clear out the flash missile robots before destroying the reactor.

yes, I'm on level 8 now.