https://www.reddit.com/r/MarvelSnap/comments/12kuafh/and_now_for_something_completely_different/
My General Advice:
So I have 3 main pieces of advice I've learned playing Marvel Snap. The only other card-like games I've played are Clash Royale and Stormbound, so maybe these might be obvious to more seasoned card game players.
Know what your opponent is playing.
You're not going to be successful in this game if you're constantly surprised by what cards your opponent drops. Understand popular deck types and what cards are normally played with other cards. If you see a Wolverine and an Electro, you know Galactus is coming. Wave on turn 5? Prepare for She-Hulk and Doom. Moon Girl means Devil Dino is coming. Move deck? Here's your free cubes (jk)
Part of this is always assume your opponent has the exact cards they need in hand. Is Black Panther played? Assume Zola is going to come. If your goal is to snap and hope that they don't have what you know will beat you, you're going to be disappointed more than not.
Snap when you think you have an advantage.
Someone else posted a guide on here a couple seasons ago with this piece of advice and I took it to heart. Don't be afraid to snap. I usually wait until AT LEAST the 3rd location is revealed in case it screws you over but if you feel you have an advantage you should snap.
For examples: do you have all the key combo cards in your hand? Snap. Do you have advantage playing into a location like Sanctum Sanctorum or Lukes Bar? Snap. You don't need to always wait until turn 6 to snap. You won't progress if you don't take risks.
Don't take this to mean just snap willy-nilly. Still be smart, but play the numbers game.
Use a deck that's versatile and surprising.
This one might be a bit controversial or maybe just my own preference but I believe to truly be great your deck needs to have at least more than 2 win conditions. And those need to be hard to see coming. This is the inverse of my first point above, you want your opponent to not know what you're going to play.
This is why I'm not a big fan of decks like Cerebro or Patriot that rely on just 1 or 2 cards to win. Not saying you can't win with those, cause you obviously can, but they're very predictable.
This may be more of an issue at the higher ranks once you're playing against players with better game-sense but if I see you've dropped Misty Knight and Shocker, I know Patriot, Blue Marvel, Ultron, etc are coming and I can do the math and know exactly whether or not I can win. Same for Cerebro. if every card you drop has 3 power it's real easy to tell what's coming down the pipe.
The Deck
First off this deck started as this deck on Snap.Fan from Wallach. So thank you Wallach if you're here. The two changes I made were adding Invisible Woman and Iron Man, both of which are key as I'll explain below. The main strategy of the deck is covered in there but if you want to read more.
The main goal is to have Invisible Woman (IW) and fill it with Ant-Man (usually comes before IW), Captain America, Valkyrie, and Titania. If you can get that off, as long as you have 4 cards and either Ant-Man, Captain America, or Mister Fantastic in a side lane buffing you, you'll win that lane based on Invisible Woman not revealing cards until the end of the game.
If you don't draw Valkyrie, or your opponent plays Cosmo on IW (which only happened to me twice in my climb surprisingly. I just don't think Cosmo is that prevalent at higher ranks) Then Iron Man is there to help win you that lane with upwards of 24 power.
Then all you need to do is use some combo of Daredevil, Pro X, Mister Fantastic, Cosmo, and Destroyer to win the other lane.
Here's the card breakdowns:
Ant-Man
Ant-Man is used to help fill up a lane for Valkyrie. His Ongoing effect is a buff for him when Valkyrie goes off. He's fine to play before Invisible Woman. His cost can also be used to play both him and Valkyrie turn 6 if needed.
Titania
Main use is to drop AFTER Valkyrie on turn 6. Don't drop before or else Valk will nerf her.
Her secondary use is also to clog up an enemy lane if they have 3 cards there. Only used this a handful of times.
If I was feeling confident and also had priority I would sometimes try to play her in a lane I knew my opponent wouldn't play in on turn 4, then drop Prof X turn 5. If you have priority then Prof X flips first and prevents her from switching sides even if your opponent plays a card there.
Daredevil
To be used to scout where to drop Prof X on turn 5. If you don't have Prof X in hand I would sometimes prioritize dropping Armor instead if I was planning to play Destroyer
Can also be used to drop Cosmo to block your opponent if you have priority
Invisible Woman
The secret sauce of this deck. Valkyrie's biggest flaw is if you have priority when you play her then you nerf your own cards but don't nerf whatever your opponent plays that turn. IW rectifies that by not playing Valk until the very end of the game no matter what.
Like I said above, surprising your opponent is the biggest advantage you can have in this game and no card is better at surprising than IW who literally hides your cards.
It's said IW is a Cosmo magnet but I only had that happen to me twice. Not sure if that's just a higher rank thing but just be warned. If it does happen then Iron Man is your friend there.
I never had to use her for this but she also protects unplayed cards from Destroyer if you need to drop him. Although she will get destroyed herself.
Armor
Mainly used in the situations where you plan on playing Destroyer and need to protect your other cards.
Can also be used as a filler in IW lane to get to 4 cards.
Mister Fantastic
Very versatile card. Can be used to get into unreachable locations.
Can be used to get power into your Prof X lane.
Can be used to buff your IW and Valk lane if you don't have Ant-Man or Captain America in them.
Captain America
The backbone of this deck. Perfect in a lane with Valk. Can have literally any 2 other cards and you'll win the lane.
Pairs well with Iron Man too in a full lane.
Cosmo
You want to use Cosmo mainly to stop Destroyer's ability.
Occasionally you'll use it to disrupt your opponent.
Never put into IW lane unless you lose Valk somehow.
Careful of putting into other lanes in case you need to drop Valk there later too, don't pigeon-hole yourself, sometimes it's best to just not play Cosmo.
Iron Man
1 of 4 lane winning cards. Drop him where you'll get the most power opposite your Destroyer lane.
Ideal lane with Iron Man would be Ant-Man, Captain America, Armor, Iron Man.
Professor X
One of my favorite cards. Can win a lane all by himself.
Obviously he's best to use with Daredevil but If I don't have DD on the board I still love to gamble on whether or not my opponent will play a card on an empty lane turn 5. Usually I'll snap if I'm feeling confident on that alone.
Easy wins on locations line Deaths Domain, Lukes Bar, Rickety Bridge, etc.
Prep his lane ahead of time with Mister Fantastic on a side lane.
Valkyrie
Obviously the star of the deck. I think her biggest strength at this time is how uncommon she is. Not many people expect her. Will she be as good once people get more familiar with her? I'm not sure. But use her surprise advantage while you can.
Very good against Shuri/Skull decks. They think their Armor will protect them but it won't.
Needs your opponent to have priority and play their cards first to have full effect. That's where IW comes in. Without IW you'd normally have to play her on turn 6, but with IW you can play her on turn 5 and not worry about her revealing until the end of the game.
Destroyer
The last win condition card. Big power output that can win a lane alone.
Obviously need to be careful about not blowing up all your other cards, use Prof X or Armor to protect them. Or drop Cosmo before you drop Destroyer to nullify his effect.
Strengths and Weaknesses
Strengths
This deck is very good against other decks that put out big outputs. It was mainly created to counter the current Shuri-heavy meta. It's also surprisingly good against popular Hit-Monkey/Bounce decks. They usually fill up a lane and then your Valkyrie easily sends them all back to 3 power. Honestly I think it's pretty strong against anything but other ongoing decks
Weaknesses
Speaking of ongoing... Devil Dino and Darkhawk are strong against this as you can't take their power away with Valkyrie's ability. But it's not impossible to win if you can get Valk and IW in their other lane and use your Destroyer to fight their Devil Dino or Darkhawk.
I know I ragged on it earlier but Patriot decks were probably the hardest decks I had to face just because him and Ka-Zar and Blue Marvel buff cards all across the board. Your Valkyrie can't do anything and Destroyer's 15 power usually isn't enough to win a lane alone.
TL:DR
Use Valkyrie behind Invisible Woman for easy cubes.
I know this was long but I just wanted to be really thorough, so thanks for reading if you did. I'll answer any questions in the comments!