Notes & Combos
This is my take on pure Crystrons, or as pure as you can make it at least. With the limit 2 on Citree, Impact and Genex you're forced to make a decision - I find impact and Citree far too useful to be without, but no undine package hurts consistency, which is why I tried to keep the deck size down.
I am happy with the extra for the most part now, but I am considering double Inzektron, which would likely replace gungnir as the need for two turns of protection is coming up more and more frequently.
The light barrier skill is purely to have a free pop with your crystron non tuners that cant be cleared before your first turn when going second (as it doesnt appear until your move, middle age mechs would also work, but field spells do not form a column and so is better against mekks), which makes synchoing into your bosses easier and facilitating a turn 2 quarion if needed with your Sulfefnir effect, plus the normal summon on a non tuner.
Dd crow is my tech of choice atm, but your only out to Necrovalley with this build is coral dragon (or Quarion, or Sam d using light barrier pop shenanigans to banish/beat over their fusion monster if playing against pure gravekeepers), so be mindful.