Harmonic ices let you get more value from derez effect. Currently, only Haas-Bioroid has derez effect, through cards like Élivágar Bifurcation, Hakarl 1.0, Divert Power.

With those cards and Wave, you could reasonably expect Echo to have about 4 to 6 subs, after rezzing it twice. 4 subs for 4, that would make this ice about the same price as Endless EULA. The added benefit would be that you absolutely need a breaker for this ice, since it would be resilient to Boomerang. This is fairly taxing to pass, but has no other effect.

At 0 strenght, it is vulnerable to Chisel and Aumakua could pay for it with no support.

At the very least, it is a 2 barrier with end the run. It could be worse.

Is this ice worth the inclusion? Yes, especially in horizontal decks, where you want inexpensive ices to protect your assets. Since this ice get more taxing as the game progress, it will complement well an asset spam strategy. And at 2 influences, it would be possible to see it splashed outside of HB.

All in all, it is a good addition to the HB toolbox. Having ways to make derez effect "add-up" is nice.

The art is well made, representing a kind of mirror image, echoing the name of the card (pun intended). The quote encapsulate the effect of the ice to perfection. Well done!

Echo looks like another NEXT Silver, but it's actually much worse. Unlike with Silver and NEXT, a newly-rezzed Echo doesn't benefit from all the other Harmonic ICE on the table. So while three rezzed NEXT Silvers have nine subs total, three rezzed Echoes have only six. If you could have 10 of each, the totals would be Silver: 100 subs, Echo: 55 subs.

Echo also looks like it combos well with derez cards like Hákarl 1.0 and Divert Power, but that isn't quite right either. Maybe you could slowly build up a behemoth Echo if it was 0 to rez, but here you're paying 2 per sub you add to your 0-str ICE.

Now if I could run 17 Echoes, would I? Maybe. I'd have tried 17 NEXT Silvers back in their day too. The problem was always that the other NEXT ICE wasn't good enough for Silver and Bronze to really shine.