Advanced Techniques guide?
Is there a page for this on the wiki somewhere or a thread about this on the forums? If not, there should be.
And don't say there aren't advanced techniques. This is not an overly complex game, but there are many advanced techniques that players aren't told and have to learn on their own or be told by friends or the forums. I'll name a few as examples.
Shield Bashing:
Tapping the shield button while an enemy is colliding with you, or at least INCREDIBLY close, will "shield bash" them and knock them away. Note that there's a small cooldown on this ability, so you can't do it twice in a row.
Reload Skipping:
For example on the Proto Gun. You can fire the first two shots, wait a few seconds, and then fire two shots again, rinse and repeat and you'll skip the reload animation. If you get the timing right, you can fire faster than you could with the reload animation bogging you down.
Shield Cancelling:
If you hold the shield button after certain attacks, you can cancel most or even all of the animation, allowing you to attack faster. For example, on the Flourish's charge attack, the vulnerability time after the final attack can be almost completely avoided by shield cancelling.
I really like to shield cancel after the first hit of the Flourish or Leviathan (preferably with max or near max attack speed for Leviathan). You can get quick attacks with no vulnerability insanely fast. You mentioned this, but I do it a lot just with the first hit, not with the three hit combo. It's hard to get used to but when you do it is pretty nice. I haven't tested it, but I'm pretty sure it's more dps if you do it correctly. I could be wrong. It also doesn't move you around because you're not doing the three hit combo that pushes you forward.
note: The first hit of the flourish has a VERY similar wide attack that the faust / avenger line has. I think it's way better than the full combo just spamming the first attack with the shield cancel. It's like swinging an avenger but super fast.
edit: Forgot to mention it's good to shield cancel after Avenger / Faust as well. That's more for protective measures because the second swing leaves you open for a while. The other swords are good to just pump out really fast damage using the shield cancel.
Hardly requires mastery, just hold left click after you press right ^^ More noticeable on the faster swords like cutters and flourishes.
I use the reload thing with antiguas. Five clicks, run two steps, fire again. Use four clicks with slower ping rates/frame lag.
About the 'mastery' comment. It's incredibly easy to do it after one hit, but to get it perfectly right getting the fastest attacks out over and over takes a while to get used to. It's definitely easier with the flourish and avenger. The leviathan, in my opinion, takes a bit of getting used to. Maybe I'm just crazy.
If you've played Gunz before, it's just basically doing the butterfly. Without the jumping.
I used rifles, I liked people who did butterflies, they died! Actually...I kinda miss that game now :(
K-stylers were such beasts.
Constantly click and unclick/ tap and untap shield button. Gives you ample movement speed and provides an increasing sum of shield bashing
Dunno if it really counts as an "advanced technique" but flinching enemies. Sort of obvious starting out when you finish your combo and knock over some lowly gremlin, but depending on the floor level and your weapon loadout you can even flinch gun puppies, alpha wolvers, and lumbers out of their attacks. It's a sort of the opposite of shield canceling, as shield canceling gives extra defense by ending your combo early in exchange for additional blocking and mobility while flinching can only be done on the last hit of your combo, allowing you to do extra damage and keep yourself safe by interrupting your enemy's attacks. This comes in in pretty handy against things like t3 red rovers and rocket puppies as simply dodging or blocking them can be unpleasant. Two-hit weapons like the Avenger, Faust, and Troika lines can flinch well, as you only need to attack twice to get your flinch and they do a big chunk of damage allowing you to flinch heartier enemies. Meanwhile the Cutter line takes forever to finish its combo and doesn't get much added umph at the end, making it less than ideal for flinching.

I think OP nailed all of them, really. I use all three (although Shield Bashing wasn't something I really thought about or looked for; it just happened randomly when I Shield Canceled) and I don't use anything beyond that.
Although, I have done this once:
If you're extremely desperate during an Arena and excess pills drop between Arena rooms, you can carry the extra into the battle if you're willing to drag them near the Party button twice. Basically, take the extra ones and drop them next to the Party Button (don't activate the button), then when you have 3 on you and the extras next to the button, step on it them drag them again into the actual Arena room. End result: 3 on you and the extra ones are sitting in the Arena, ready and waiting for you to pick up after you use up the ones you're carrying.
I wouldn't call it advanced, nor would I give it a name, but it's certainly thinking outside of the box.
Beyond that:
-Memorizing how many hits it takes to kill certain enemies (especially when solo). e.g. For solo Jelly runs, Slimes will die to 3 hits from an Ascended Calibur on Depth 15, and 3 hits from AC + 1 hit from Master Blaster on Depth 16.
-Carrying a "4th" potion of a certain type by activating one and picking up another to take it's place (read: lift one over your head so you can carry the last one).
I think that's really it...

I do all three without really knowing it. :D
Cancelling is incredibly useful on the DA's special, otherwise you get piled by the monsters around you. It took me about 5 deaths to realise that.
Especially in Arenas, but also in the Jelly Castle, Jade Tangle and some Danger Rooms, if there are any unused health capsules laying around I like "dragging" them beyond party buttons. It goes like this:
1) Unload your inventory of health capsules close to the party button (careful not to step on it yet).
2) Go back and pick up spare health capsules.
3) Step on the party button; move into the area that opened up and unload your health capsules there.
4) Go back to the party button and pick up the health capsules you dropped there.
This gives you some extra healing for especially tough areas. It also allows you to heal yourself in the Arena and still leave with a respectable number of health capsules for later.
The same can be done with vials, to give you some extra throwing fodder.
Faster Charge Attacks:
You can release a charge attack approximately half a second before it gives the visual cue that it's ready. Admittedly it's not a lot, but it may be enough to save your patoot if you're being chased.
Shield Switching (uncomfirmed):
From what I can tell, if you switch weapons and then shield IMMEDIATELY after you can skip the switch animation, thus allowing a faster switch. This is unconfirmed, and based mostly on theory and my own experiences.
Shield Invuln (unconfirmed):
There's a half a second of invulnerability time after a successful shield (as in, after an attack hits your shield.) This is enough to escape spikes if you are at the very edge of them, or to charge through a group of enemies. However, if your shield BREAKS, you will take damage and thus have a standard invuln time. This is unconfirmed, and based mostly on theory and my own experiences.
Explosive Jelly Projectile:
You can shield bash an explosive jelly at any time, even when it's "dead" and its timer starts ticking. If you time it right, you can bash the jelly into a group of enemies and use it as an improvised bomb. You can do similar things with slow-attacking enemies like Lumber with enough timing and skill if you manage to bash them right as they begin their attack.
Apart from the Jelly Projectile one, these don't sound like 'advanced techniques' but more like animation glitches...
But I suppose while the ability to use these methods are they and they work in favor of the player I'll be doing it from now on :P

Which weapons does this hold true for? I've noticed it works for my Ascended Calibur, but not really for my Avenger.
I wouldn't call them glitches. I honestly think they're intentional.
It's not that hard to make shields hold to the same global cooldown as every other action. I don't know how animation cancelling via shield could possibly be accidental.
Why TRY to bash the jellies with your shield after they start counting down, and not just hit them with a sword, does the same thing and works everytime.

Swords = a bit more vulnerable to getting damaged
AND some swords don't have a big knockback like the Cutter series
I'm going to make up some terms for the fun of it...
-Bomber Kiting: For melee-heavy groups with a bomber, have the bomber intentionally piss off a mass of mobs, and kite them in a circle while you leap in with charge attacks at opportune times. (Esp. awesome if bomber has a graviton bomb to follow up with after initial aggro.)
-Bullet Tanking: Trade off with group members on shield-blocking waves of bullets while the others shoot or leap in with charge attacks. Alternate versions involve "pulling aggro" by smacking or standing closer to Gun-Puppies and turning them away from the group.
-Guiding Rocket Puppy rockets into other Rocket Puppies.
-Cooperation: Super secret special tactic... involves being conscious of your other party members, and can include: knocking mobs away from allies before they get hit, pulling aggro and kiting while another player attacks without risk of being hit, NOT knocking mobs mid-attack animation into party members, NOT shooting explosive boxes party members are next to, and generally attempting to carry your own weight and do more than pill hog.
You guys forgot shield charging which is one the my most often used tactis.
When Shielding if you hold down attack and then release you're shield you will already have begun the charging animation, thus saving you the first swing to charge. Making it a little bit faster and safer.
"-Cooperation: Super secret special tactic... involves being conscious of your other party members"
I don't think this was an intended game mechanic. Anyone who uses it should be banned.
"-Cooperation: Super secret special tactic... involves being conscious of your other party members, and can include: knocking mobs away from allies before they get hit, pulling aggro and kiting while another player attacks without risk of being hit, NOT knocking mobs mid-attack animation into party members, NOT shooting explosive boxes party members are next to, and generally attempting to carry your own weight and do more than pill hog."
The number of times i've had to explain that it might be best to retreat while firing guns instead of charging into a huge group... this tactic is clearly meant for the most advanced players only.
Knowing your enemies' weaknesses:
From my time in the clockworks, I have found that Wolves are weak against piercing damage. This can also be said for the various flying monsters, like those bats and butterflies. Those worker dudes are also weak against piercing.
Certain weapons consistently cancel out Puppies' fire. I use the spur series specifically to keep puppies at bay.
I don't know if this would be considered "advanced" but you can turn on the ability to see the amount of damage you are doing in settings. White is normal, yellow is effective, and gray is ineffective.
I've always unconcsiously shield canceled because it's such a common thing in games (DMC1 shotgun/roll cancell FTW!), but tonight I started paying attention to when/how I do it. I use a Khorovod so it makes a huge difference. Hit, shield, hit, shield, hit, shield...
At this point I'm so sick of it that I'd rather it was nerfed. That, or weapon delay should be split between the startup animation of an attack and the recovery, rather than only the recovery time. Canceling the recovery animation wouldn't be such a big deal then.
"I don't know if this would be considered 'advanced' but you can turn on the ability to see the amount of damage you are doing in settings. White is normal, yellow is effective, and gray is ineffective."
This is a good thing for new players to know regardless; I don't know what portion of the population dives right into the options menu after starting, but knowing that the option to turn on numbers is in there is a good thing to know.
This is a good thing for new players to know regardless; I don't know what portion of the population dives right into the options menu after starting, but knowing that the option to turn on numbers is in there is a good thing to know.
I did and I always do, with ANY new game I play, I always hit options first, video settings, chat, etc.

I only knew about that option because I was here before they took it away (brought it back as an option)
I tried to rouse interest in this several months ago:
http://wiki.spiralknights.com/Strategies
Edit as you will. A lot of the names are ones I'd made up, since I didn't see anyone else using them on the forums. Maybe we can get a new (or rather old) page up and running?
For those who regularly edit wikis, I've already created redirect pages from "Techniques" and I think "Tactics" as well...
Hell yes for wikis.
When a treant or alpha wolver comes at you, move out of the way, come behind them, attack, and repeat. This has helped me survive many of the wolver attacks.

Gun switching- you shoot your gun until it only has one bullet till it has to reload then you shield cancel the animation of the gun and switch to another gun as fast as possible shoot shield cancel change Back to the other gun and just keep repeating this which will make It so that you don't have to reload and a high dps
You can also do this with swords but you might wanna ask a elite swordsman for help with that.
i only recently saw myself shield cancelling, and didnt even think of it as such. really interesting technique to try mastering...
also, would the average dps be better on 2 shot guns too, like autoguns or the xxxtech series?