Sometimes it's good to revisit old ice in light of new icebreakers.

Most ice breakers break Neutral Katana for 3 or 4. There are a few exceptions, the most important two are:

• Mimic is old and not really all that popular anymore. It breaks for 1 but hits a wall with any ice that's stronger than 3 without support. Just to name a few Assassin, Archer (more playable in Jemison), Cortex Lock, Data Raven. You don't really want to Mimic unless you have a backup plan that can breaker during the current run (i.e. not Parasite). There's just too much ice you don't want to faceplant into.
• Na'Not'K breaks for 1 if the Katana is in a two ice server (4 otherwise). Since Na'Not'K is likely to become a very popular killer for shapers and potentially anarchs as well (only 1 influence) this strongly impacts the amount of tax you can get from Neutral Katana.

While Mimic is less of a threat these days Na'Not'K is just getting started. And while as a faceplant trap the runner has to pay 4 for Na'Not'K if you have 4 in hand you can easily rez a Cortex Lock as well so a runner with Na'Not'K has to reserve 4 anyway or risk severe net damage.

Sorry Katana, but you've been replaced.

EDIT: A previous version said that Na'Not'K breaks Cortex Lock for 7. This is incorrect, even in a single ice server with just Cortex Lock Na'Not'K gets +1 strength.

The reason for the trash cost that gets boosted by 3 for each hosted card is to make it unappealing to trash the RecStudio in order to trash both the installed cards. To be that way the sum of the trash cost of the installed cards has to not exceed the trash cost of the RecStudio with two cards on it, which is 9.

Here's the division in assets (up to Free Mars of Red Sands cycle has been released at time of writing):

Trash cost 0 (10 cards)

(Not shown to keep review small and it's not really relevant)

Trash cost 1 (9 cards)

...

Trash cost 2 (26 cards)

...

Trash cost 3 (42 cards)

...

Trash cost 4 (22 cards)

...

Trash cost 5 (15 cards)

Alexa Belsky, Broadcast Square, Corporate Town, Cybernetics Court, Director Haas, Eve Campaign, Genetics Pavilion, Hostile Infrastructure, Ibrahim Salem, Jeeves Model Bioroids, Marked Accounts, Private Contracts, Pālanā Agroplex, Victoria Jenkins, Worlds Plaza

Trash cost 6 (3 cards)

Chairman Hiro, Illegal Arms Factory, Reality Threedee

Trash cost 7 (1 cards)

The Board

Trash cost 8 (1 cards)

Sealed Vault

While some 5 cards are not uncommon (Eve Campaign, Hostile Infrastructure, Jeeves Model Bioroids) the 6 and up cards are pretty rarely seen in actual play. And the 5 cards are not the kind you'd normally put together in NBN (or what you'd inport a •••• card for in HB). So I think it's safe to say that it's extremely unlikely that anyone will ever put two cards in a Rec Studio that together will cost more to trash than the RecStudio.

This means that RecStudio doesn't add risk unless the runner has a card that lets them trash an asset but only one asset. The only card that comes close is Drive By but that only works on unrezzed cards. Derezzing is also harmless, the cards hosted on it remain hosted (according to FAQ 4.0).

While the RecStudio doesn't add risk is does cost a deck slot, 2 to rez and is positional (it has to be rezzed before the assets and agendas to throw on it). That's still quite a few downsides, is the effect even worth it?

Frankly, I doubt it. Theoretically the benefit of installing multiple assets and/or agendas in the same server is that you only need a big chunk of ice in front of it to keep both installed cards safe. In practice runners get into the most heavily protected servers, especially with the rather weak ice that NBN tends to employ. And once in the runner simply can kill two birds with one stone. You just end up painting a bigger bullseye on your server.

There are of course janky plays. Since the runner has to access all cards when accessing you could do stuff like a double Edge of World server.

You would think there are some nasty sysops who get to play in the RecStudio as well but all sysops are upgrades. Characters, which are assets, are also harmless when accessed. Executives aren't traps either, except for Toshiyuki Sakai if you squint your eyes a bit.

I simply fail to see a realistic use case for Full Immersion RecStudio.

From a Red Sands cycle perspective Expo Grid has a useful property compared to just smashing down another Pad Campaign: you can do with less remotes. This is useful because of Aeneas Informant and Security Testing (and to a lesser extent Temüjin Contract). A trivial piece of ice that costs 2 to break makes the server uninteresting for money gaining purposes.

The benefit is a bit too small to justify the ••• influence cost but in Weyland it's interesting.

This present an interesting logic problem: can Troll get trashed by Forked?

Let's recap. The text of Forked says: "The first time you break all subroutines on a sentry during this run, trash that sentry."

Intuitively one would say you break all subroutines that exist, which are none so Troll instantly dies to Forked.

Another interpretation is that you don't break all subroutines. You've broken no subroutines.

Another interesting conundrum: can Inversificator swap Troll?

Surprisingly there is a lot of ice with one sub. I've counted 90 ice with 1 sub, 91 ice with multiple subs, 12 ice with a variable number of subs and 1 ice without any subs (Troll). That means Vamadeva can break 46% of all ice. Assuming the average division of ice is something like 33% barrier, 33% sentry, 33% code gate, 1% trap / other special that means Vamadeva breaks 13% more ice than a regular breaker.

Here's the thing though: because there's no ice breaker that only works on ice with more than one sub you cannot cover all the ice without either a less efficient AI or a conventional set of breakers. And while the break/pump stats on Vamadeva are the same as on Corroder that means it's not the most efficient at breaking barriers (Paperclip). Similarly it's not the best at code gates either due to Gordian Blade being more efficient if there are multiple code gates.

So what you end up with is an AI that sucks at the things AI's are supposed to be good at: working on significantly more cards than normal breakers. Vamadeva is efficient (1/1/2 break/pump/strength) but not top efficient.

Another criminal AI, Mammon, has no restrictions on what it can be used on and isn't much less efficient (2 to pump means it's 1 less efficient on half the ice).

I don't think this is a card that would be useful in practice. Though looking at knowthemeta it's in 5% of the decks, so maybe I'm wrong.