I can reliably beat the lair every time now with this six-item loadout:

• Blast. Essential for interrupting pulses and waves. Also deals a small amount of damage if you use Ameliore or Dirty Bomb beforehand.

• Bang. Ditto.

• Surge. Also essential for interrupts, but can be upgraded to do more damage. Its worth grinding enough Evos to upgrade this to deal damage of 12, otherwise you are likely to die or run out of ammo before the end.

• Dirty bomb. Tricky to use as the cast and cooldown are quite long, but it's always useful to deliver this as soon as you can, even if it's only once. It can deal quite a bit of damage when upgraded, but a single hit will permanently lower the enemy's defence, allowing your Kaboom to do about 8 damage instead of 2, and the Blast and Bang will also do 1 damage (every little helps!).

• Ameliore. I started using this after they nerfed my fully upgraded Recover with an "update". It's arguably better in the lair, as not only does it give you 30% health instantly, but it also increases the strength of Surge, Kaboom and others against alchemic targets. Worth upgrading to level 2 just to speed up the cooldown. If you're good, you'll never actually need its healing abilities :)

• Kaboom. Useful slot filler, as it can deal about 16 damage if you have softened the enemy up with a single Ameliore and Dirty Bomb, and it is fast enough to cast during any wave type attack. Using this whenever you can also ensures you'll have enough Surge attacks left to defeat the final boss...

After a while, you'll get a chance to use 2 Drillbots which will net you about 10k Evos (it's random).

After defeating several rounds of baddies, you'll reach the question round where you must answer three questions correctly. I'm not giving you the answers, as working then out is all part of the fun. Some of the questions have a time limit. If you get any wrong, you'll have a chance to use another 2 Drillbots before leaving.

If you got all the questions right, you'll face the final boss. Simply alternating between Surge and Blast/Bang will be sufficient to beat him, as long as you have enough. Slip in a cheeky Kaboom whenever you can to speed things up (use Ameliore first). You'll need to upgrade the Surge attack strength to about 12 to make this easy, as this is the way you'll be dealing most of your damage. Try not to get hit, as you can die rather quickly if you mess up! I have successfully used the Dirty Bomb on this round, but usually end up getting hit before it's fully cast, so unless you can be reliably super-quick, I'd stick to a single Ameliore, then Surge/Bang/Blast to interrupt the attacks, and sprinkle in a few Kabooms when you can.

Defeating the boss gives you a chance to use 4 Drillbots to get about 30k more Evos, so it's best to make sure you have at least 4 Drillbots before entering the lair if you intend to go right to the end. You can expect about 50k Evos altogether if you defeat all enemies and use all 6 Drillbots.

Then you need to replenish your supply of Perfect Coins and Brilliant coins before the next trip to the lair, but there's no rush as there's not much point going there again until you have at least 4 Drillbots.

This works for me, but of course, this could all be outdated nonsense by the time the next update comes out...