What to Look For in a Mystery Game
Mystery Game tournaments are a fixture at midwest events like Frosty Faustings, and sometimes people host them online. Because it's built out of the FGC, you usually see a lot of fighting games (but plenty of other genres can appear, from puzzle to shooter to racing...)
This is going to be a guide for how to quickly figure out a fighting game you've never played before. Puzzle and other genre fundamentals are a whole thing I'm just not equipped to talk about!
First tip: If your character has a slide, use it!
Slides in fighting games (especially old ones) are funny and can lead to a guessing game that's usually in your favor, because no one's practiced punishes (unless they have played this game before). A slide is your ticket in. It probably goes under fireballs, or at least standing buttons, which immediately cuts stuff off from the other player.
Second tip: Try out button combos straight away.
Fighting games only work because you can throw the other guy. This is not up for debate. What is up for debate is how you throw people, and a lot of the time, it's LP+LK, or two punches, or Punch + Guard in 3D games. You can also expect lots of other useful things to be locked behind button combos. Heavy Slash in half the Samurai Shodown games, universal overheads, dashes or jumps, whatever you wanna call KOF C+D attacks... or even super moves, for some very bold games (like Astra Superstars).
Third tip: Throw people.
You already know throwing is good. Throws are usually fast and they usually take more effort to counter than to use. Some games don't even have throw teching! The older a game is, the more likely throwing is strong, and that hitting a reversal is hard. If someone blocks, throw them. Are they going to stop blocking? If they stop blocking, they lose. Some particularly broken games will even let you guarantee throws either after a tick (i.e. blocked attack) or on their wakeup, because game design is hard.
Fourth tip: Jump a lot.
Like throwing, jumping is basically really good. Not every character's anti-air game is good, and it forces them to block. This advice gets worse the later you are in bracket and the more freedom you have in terms of juggle combos, but it'll get you a few wins at least. And if they block, then you can profit off empty jump throw. If they get hit, sweep them. Maybe sweep them if they block too, just in case.
Fifth Tip: Check your common special inputs.
At the start of round 1, check your quarter-circles, half-circles, shoryuken motions, charge inputs, and if it looks like anime, down-down inputs. You don't have to know a lot to intuit why a fireball and dp are good if you've played a fighting game before. You might just find a move that wins you the game, straight up.
Sixth, and Final Tip: Mirror Match.
For confident players only. If you lose Round 1 of your given game, pick the same character as the opponent. I think this works better if the match wasn't even close. It's kinda hard to intuit how good a character is from just their design. But if you're playing the same character... the better player will win.
Mystery Game formats are always a pretty fun time, so hopefully this helps someone have fun. And win.