Good 1-copy card for HB decks still building the early rotation sets.

Super punishing for the Runner to trash. And the effect is handy to have. Not gamebreaking, but it might turn an early game Viktor 1.0 with an Eli 1.0 behind it into an unstoppable wall. So basically pretty good early on, and an annoying threat the rest of the game.

A tweaked and slightly weaker Desperado (but that card was strong as heck). With supporting cards like Red Team the runs you'd make anyway become so much more rewarding, and then you don't have to do boring stuff like "manage economy" when you could be running.

One upside (that might not be initially evident) is Pennyshaver can be used as bait for an expensive Corp combo like Public Trail into Retribution (especially if you're slow or lazy at taking the credits off the console). So you might get a tempo swing from that.

Absolutely terrific card. Low effort for the Runner, huge effort for the Corp. Maybe they take a turn off purging, or maybe they let it ride and you get 4-8+ credits out of them for a re-rez. Either way, I think this is pretty overtuned as far as the new cards go. For example in System Gateway if your corp opponent has an advanced Pharos you can more or less forget about it.

And if Acacia is alive and kicking it's basically free money (or the threat of it)!

I wasn't really a fan of single use breakers back in the Faerie days, but Mayfly fits the System Gateway decks really well, and is more powerful since it can smash through any ice type.

It can be a surprise to the Corp when they think they're safe early game (maybe behind a single ETR barrier or whatever), and even late game with support from econ cards like Overclock or Leech. Even the mental factor of the threat of Mayfly can stop a tentative Corp from rushing an agenda they otherwise would feel safe going for.

Downside is you might be tempted to just rely on Mayfly usage instead of setting up the rest of your breaker suite, so it can lead to poor tempo if you're not paying attention (such as installing and running with Mayfly on a turn that doesn't pay off, and then being a "proper" install behind).

Also in terms of the name and art I think NISEI did a bang up job. Simple and effective drawing, and you basically immediately know what the card will do from the name alone. Solid quote is just gravy.

If you can swing the Influence, this is one of the best direct replacement cards in Netrunner, as it's so drastically superior to Pop-up Window. The number of early scores I could get out in an HB or NBN deck from having a hard ETR gear check is crazy. Really cool card, not overpowered, not crazy, but just good enough to get excited about if you were running Pop-up before.