Sediment Shield: Permanent (8 Earth quanta)
Blocks 2 damage from creature attacks. If you are attacked this turn, the shield loses 1 power, if you aren't attacked this turn, the shield gains 2 power. Permanent destruction deducts 3 power.
An upgrade could make it so that it has to be a successful attack to reduce the shield power.
Possible use: Along Sundials it would be a good card, since Earth/Time is a natural combo, so you could stall with Sundials up to theoretically 26 blockage, and destroy the enemy's weapon with a Pulverizer (Earth/Gravity, just one Gravity needed). Earth/Gravity absolute control or lockdown or whatever could also work.
Icicle Shield: Permanent (5 Water quanta)
Summons 5 Ice Columns which absorb damage from a single source. Summons 5 more Ice Columns every turn, up to a maximum of 5. The shield isn't destroyed on 0 charges, but is removed by permanent destruction wholesomely.
An upgrade removes the maximum cap, letting you stall or control the enemy creatures enough to grow the shield large.
Use: Blocks the first five attacks, every turn. After the upgrade it also builds up if the enemy is having less than 5 damage dealers, and can be used with a Sundial to get 4-5 more Columns every turn.
Diccusion!
Ok now i can comment, hopefully i'll say something constructive, but that's up to you to decide
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Let's take the uped version of sediment shield. As you said, you get some sudials and than all of the sudden you have a 15+ shield. Break trough that! Kinda OP imo.
And for icicle it would be worth getting an PA just to keep that shield(i'm yet again talking about the uped version again). You get earth mark, get some uped sundials, and all the rest is obvious. You get the shield and you win(well except fire lance or something but still...). Again, OP.
Ok now that was the criticism part. Time to be constructive
I cannot think of anything good to make the uped versions less OP, maybe except making the uped versions just cost less quantums. Sorry for actually not being so constructive...
PS: I think it's not your bad, it's just the thing that sundials are OP, making your shields OP. But this is the game, we have to adapt to it.