Well this is an interesting card. It drains credits continuously but that's something a good criminal player should be able to play around fairly easily (though beware of NBN tricks like Closed Accounts).

Reducing the corp's hand size would be meh for anarch and shapers but it's pretty good for criminals now that Jackson Howard has retired. The key is agenda flood. With sufficient remote pressure corps will either need to keep agenda's they draw in their hand (potentially pushing out other useful cards) or in archives (dangerous, very dangerous). Now normally the chance of accessing an agenda in HQ with a single access is 20% (1/5) if there's 1 agenda in there, 40% if 2, 60% if 3, etc. With hand size 4 it's 25% (1/4) if there's 1 agenda in there, 50% if 2, etc.

Assume for a moment that the corp has 2 agenda's on hand. That's a fairly common situation. That means Lewi Guilherme will increase you chance of stealing an agenda on single access by 10%.

A subtle but important side effect is that by reducing the corp's hand size you're simultaneously reducing the corp's discretionary hand size by an equal or higher degree. What I mean with discretionary hand size is the spots the corp has in their hand for cards they choose to keep in hand to play at a later moment but don't have to keep. Admittedly it's a somewhat blurry concept since the corp could just discard agenda's as well, but generally corp's will feel compelled to keep agenda's whereas keeping assets and operations and such is a tactical choice.

Assuming the corp has two agenda's on hand again. That means they've got 3 spots for all their IPO's, BOOM!'s, etc. If you reduce the hand size to 4 suddenly the space for non-agenda cards goes down to 2, meaning a 33% decrease. That forces very painful choices for the corp, e.g. it will be difficult to combine a deathblow setup with anything like economy support. Of course as a runner you will generally not know how hard this effect is hitting, but it will impact the corp's game to some degree at least.

Note that you don't have to keep Guilherme installed. You can just decide to trash him if you don't see him earning his weight or you have a replacement on hand. Beware through when playing against Skorpios if you trash him.

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It's janky, but this is another target for Dr. Lovegood to turn off the negative. —

Although it's appealing to see this primarily through the lens of Apex' big weakness (no non-virtual resources) the bigger effect on Apex may well be to give it access to a wide range of very efficient tools cheaply. Although many of the most expensive programs have rotated out a few remain:

  • Mass-Driver is rather situational (2 per sub but you get to ignore up to 3 subs on the next piece of ice) but if it works it's really quite nice. I wouldn't use it without something like Inversificator to help shape the ice though and that means a heavy import price.
  • Morning Star is a very efficient (though memory hungry) fixed strength fracter: 1 for any number of barrier subs as long as that barrier has strength 5 or less (good thing for the corps that Parasite is gone, Ice Carver isn't however).
  • Inversificator is on the cheap side of what I'd call expensive (the 6+ range) but it's an excellent breaker (and restricted).

Hardware has seen some of its most expensive pieces go away in the rotation as well, but the all time biggest credit eater is still there: Monolith. It doesn't synergize very well with Apex since the ability to prevent brain or net damage is worse than what Heartbeat already gives you but the 3 is nice and I guess it's at least a nice surprise during a game to turn up a hugely expensive console. Oh, wait. Console. Right... Yeah, it doesn't synergize with Apex at all unless you want to skip on Heartbeat and you don't want to skip on one of the absolute best Apex cards.

Ignoring the consoles the most expensive hardware is Adjusted Matrix. I guess it could be nice in the right deck, having the option to click through ice could help when Endless Hunger doesn't quite cut it.

On the resource side Rachel Beckman is nice. The shards (Eden, Hades and Utopia) were already available to Apex (virtual) and could already be installed without cost under certain circumstances, but having a way to buy them for a few clicks and otherwise leaving them as fuel is good for Apex. Plus the shards (and Beckman) are only 1 influence so they won't bust the budget.

Liberated Account becomes much more efficient if you only pay for it. Laguna Velasco District and Professional Contacts are also interesting, especially given Apex' need to draw cards.

A somewhat circular but slightly amusing option is to save 5 on installing Assimilator. Just in case you wanted to have a second one handy.

Aside from the expensive stuff Assimilator is perhaps even more effective just doing its thing in your deck since it lets you replace + X to install a card normally by Apex ability + . I don't expect this to be a complete game changer that will make Apex viable on a championship level, but my gut feeling is that it will make building a somewhat competitive Apex deck a lot easier.

Addendum: What I forgot to mention is that Assimilator has a small but nice effect on the game. It lets Apex have more hidden information in the form of face down cards. Normally only the corp lets their opponent play a guessing game.

Addendum 2: There's also a nice benefit with Apocalypse in that if you have an Assimilator on hand when you Apocalypse you can recover much faster from it than the corp by flipping your most valuable cards face up again.

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Liberated Account gets its credits when installed, and Assimilator flips instead of installing, so a flipped Liberated would have 0 credits and would immediately get trashed. Monolith also wouldn’t get its “on install” effect (though you never suggested it would). —
I was waiting for someone to point out an obvious error that I missed in hindsight. My reviews just don't feel the same without it. ;P Thanks. —
Adjusted Matrix doesn't work either since it needs to be installed from hand onto a breaker. —

By Any Means is a potentially powerful event. Being a priority event, you'll need it in hand when your turn begins (no Same Old Thing). After spending a and 2 to play it, you have 3 or possibly more s to make it worth the investment. Ideally then, you'll want to use all remaining s to make runs. This could be worth it against an asset spam deck. You may end up saving a lot of s if you can access certain assets/upgrades. But as you do "trash" the cards, CTM and Hostile Infrastructure still trigger. And you have to pay the Gagarin tax. You'll probably trash 3 or 4 cards max.

This card seems to be better utilized against central servers with multi-access support. You can build your deck around this concept, but you never know if you will be facing an asset-spam deck. So, lets say we hammer the centrals. one, By Any Means, 2, Legwork, 3, The Maker's Eye, 4, another plain old run against R&D or HQ. This will net you 7 trashed corporation cards, including that costly Jeeves, and those un-trashable ICE and Operations. That seems very worth it. But you need to have the correct cards in hand, in play, and the credits to get into the servers; a tall order. And worth noting is the fact that this card can kill you. You have to trash any cards you access. So access too many cards and you could flatline yourself. At least the corporation doesn't have the ability to spring ambushes. But you'll probably need damage protection in the form of I've Had Worse or Guru Davinder (expensive). And those agendas you access? Trashed. Maybe have a Film Critic installed to help with that.

Anyway, I'm out of work in five minutes so... A potentially good card, but it needs a lot of support cards to make it worth it.

Edit:

So what about this with God of War, Counter Surveillance, and Jarogniew Mercs for protection?

#4 Deep Data Mining ! —

If I am reading it right, this card will let Apex use non-virtual resources.

Apex is not prevented from including non-virtual resources in his deck, he is only prevented from installing them:

You cannot install non-virtual resources.

And per the FAQ, facedown cards have no type or subtype:

Facedown Runner Cards

Runner cards that are installed or turned facedown do not have a name, type or a subtype, and their abilities are not active.

So it seems Apex can install virtual resources facedown with his ability, then use Assimilator to flip them faceup, bypassing costs and install restrictions. I definitely want to use this to get an Aesop's Pawnshop into play!

Yeah, but to get it face down on the table, you need to install it with either Apex or Hunting Grounds. I don't think it loses its subtype until after the install. So it is like the one Region per server rule. You could do it, and no one would neccessarily know, but it would be against the rules. I think anyway. —
Well according to the UFAC above, I guess Apex can use this for non-virtual resources. That's pretty cool I guess. Apex needs help because he sucks. More exciting to me though is the ability to use Cyber-Cypher on any server! —
Not sure why Cryber-Cypher is that exciting given that you don't pay the install cost. Gordian Blade would seem to be strictly better, —
Forgot the 4 strength, still imagine other cards will be more impactful in the hardware/resource sphere. —

Witch Doctor

Pros:

Guaranteed net damage disregarding bypass tricks or AI breakers

requires only 1-2 credits to use, 1 net damage could mean the differences between a painful Snare! and a deadly one.

Synergy with other psi and AP cards like Hyoubu Research Facility, Upayoga, Nisei Division: The Next Generation, and Synth DNA Modification

Cons:

Can be trivially broken by most AI

Small effect might not be meaningful enough for jinteki decks

Overall a replacement for the now rotated Data Mine, might be worth a look in some AgInfusion: New Miracles for a New World or Jinteki: Potential Unleashed decks.

Might be good with Tori to score a brain damage. —
Doesn't the fact that it trashes itself make it less synergistic with Upayoga? Even if you shenanigans it out without it firing, a successful fire off of Upayoga will also trash it, according to its sub. —