Make sure you have 5 soldiers available on your team before starting this, you will need the firepower! And get the best gear that is available to you this early.
The first level of the tower is pretty easy (comparatively). Deal with the first few MECs, which have 4 health and 3 armor points, so rarely any oneshot kills!!!).
Make use of Shen's hacking ability to strengten your numbers and give the hostile MECs another target. The MECs have really bad aim, so if you want, you can use the self destruct on them with any hacked unit, but on this difficulty it will not kill a MEC on full health. But this will be essential later.
Make sure every soldier is in position to use the elevator before activating it.
make sure you leave lst with your heavy hitters, in case you need to take down a few of those MECs coming at you with self destruct. If you can, stay out of their sight, so they will attack any hacked unit, go into overwatch or self destruct mode to avoid fire. Reaction shots of them are not that dangerous, because they have low aim anyway.
Next level deal with the first 4 turrets, then enter the middle room with all soldiers before activating SPARK so you don't have to waste any action points to get in there next round before the poison gas is released.
Take position at the far side of the room behind full cover and reload.
now activate spark.
A few turrets will spawn, if possible try to take them all out so you can move spark all the way to the deactivation button with his overdrive ability to turn it off next round.
Now, as soon as the gas is off i started to sprint my units as near as possible to the elevators.
That means I couldn't take any shots at the turrets and incoming MECs, but tried to stay out of line of sight of the turrets. You should be able to avoid any reaction shots of the turrets, if you get hit, they won't kill you. So this strategy was worth it IMO.
You can choose to fight, but then you only move at half the speed across the room and have to make damn sure your shots kill or you will be overwhelmed.
Top of the Tower
This is the most tricky part.
Fighting the sectopod with essentially noob soldiers is all but impossible and neither Lily nor SPARK are allowed to die so be really carefull when and where to position them.
It took a whole lot of reloading and experimenting with tactics and a bit of luck to succeed.
First round I used the few grenades and SPARK's rocket to reduce it's armor as much as possible and deal as much damage as you can (lots of one damage hits are likely.
A ouple MECS will come in and the sectopode will take shots at you and will prioritize SPARK. It is likely you will take some damage here.
If you are lucky the sectopod moves near one of the two generators.
ignore the MECS and use combat protocol to deal more damage and shoot whatever you have at it.
if you have the freeze bomb use it to reduce one action point of the sectopod.
two more MECS will come in and another round of surviving somehow.
Now is your chance.
use Shen to hack the sectopod to take control not of itself but of every MEC on the roof. This should be 4 plus one back in teh corner that likely remained hidden until now.
if you succeed (roughly 50/50) you know have 5 walking bombs you can throw at the sectopod and remove any remainign armor and deal between 10-15 damage.
With any luck you can now take that thing down in one or two rounds.
if either SPARK or Lily take too much damage, remove them from the line of fire at least until you can deliver the kill shot.
Good luck!
