How can I counter enemy away teams?

I've reached sector 8 a few times, though I have yet to destroy the final boss. Without a doubt the one factor that most affects my success right now is whether I get an enemy with a teleporter.

I invariably end up losing a crew member or two when I'm attacked, and I typically lose the fight as well once that's happened. I usually scramble my crew to the fight as fast as I can, but they only win when they outnumber the enemies and even then sometimes a friendly goes down (or if the enemy is in a 2-square room I can't even outnumber them).

Is there a tactic or technique that I'm missing here to make enemy away teams less horrible? Obviously a Mantis crew member helps when you can get one, but even that doesn't seem to give me much edge.

Solution 1:

The combat effectiveness of your crew varies, and additionally they level up as they fight.

For instance, Engi and Zoltan crew members have lower health than Humans, Slugs, Mantis, or Rock crew members. Mantis crew also have a bonus to combat damage. Engi and Zoltan especially are worthless in a fight - be ready to move them quickly, and plan on any combat taking a while if you can't get the enemies into the medbay quickly.

I tend to assign at least one, but ideally two of my crew members to "security detail" - they're the ones that get pulled into rooms to fight if there are enemy boarders. They're also typically my away team if I have a teleporter. I will tend to pick Mantis first for this, then Rock, and finally Human. If I've got to double up and have my subsystem crew work security detail, I tend to leave the weapon officer and pilot alone - other crewmates will pull security detail before I'll move them.

Some other tips:

• As has been noted, the best place to fight is in your medbay, as you'll constantly regenerate health so long as the medbay is undamaged and powered up.
• I will sometimes open doors to route enemies into 2-square rooms, or let them have a particular subsystem (ie, sensors or door control) if they're likely to move into a more advantageous room after they've damaged it.
• Remember that you can pause (with space) and issue orders - if you need to shuffle crew around, and you've got a lot going on between ship combat and dealing with boarders, this can save your crew, especially if you're like me and you tend to click doors rather than crew in a panic.
• In combat, you'll still take damage as long as you're in the room with the enemy, so make sure you leave enough health on your crew to make it out of the room before they die.
• If you've decompressed part of the ship, remember that you'll take damage passing through it, so keep that in mind as well if the decompressed portions of the ship are between your crew and the medbay.
• Upgrade doors will help a lot, giving you more time to "vent" them to death or time for you to finish the fight with the ship before taking care of the boarders. Just remember robots don't need oxygen and if your door controls get destroyed you can't close doors, which means you could lose oxygen.

Solution 2:

Doors.

Upgrading the door subsystem is cheap - only 20 scrap to upgrade to blast doors to slow the enemy down, and another 50 to upgrade those blast doors.

With blast doors, the enemy's movement is curtailed, so you generally have time to attack them a bit, heal up, then go back to finish them off, without them having the run of the ship in the meanwhile.

Plus if you're venting the oxygen to asphyxiate them, blast doors mean they can't just move into oxygenated areas, but stand there hammering on the blast doors while suffocating. They might not die completely, but they will at least be weakened by the time they get through.

Since the 20-scrap upgrade also slows down the rate at which fires spread, it's something I almost always pick up early on.

(As others have said, sending better fighters to repel the boarders gives you the advantage in direct combat, and you should do that as well. But doors give a surprisingly powerful indirect advantage.)