There's a surprising amount of extra content to unlock in the Saturn version of Fighting Vipers, and because some of these bonuses have obnoxious/obtuse unlock methods, I present to you the (near) definitive guide to unlocking every secret in this game. As I am what some would call a Nighttime Ramblin' kind of man, I'm going to cover these secrets in almost certainly unnecessary depth. If you'd much rather just have a boring cut-and-dry list, just click here, you lazy bastard.

I'm going to be systematic here- I'll cover the stuff you can unlock in every version first, then move on to the exclusive Japanese content.

All Versions

To begin, let's look at those secret fighters...

To Unlock: Complete Arcade Mode on any difficulty setting.
Despite his apperance, Mahler isn't the final boss! He's actually a slightly smaller and weaker version of him, looking exactly the same in every other respect. This, however, does not make him any less insufferable to fight against when in the hands of a human player, because he retains the boss-man's insane chain combos, and most of his strength. Seriously, you can just mash any buttons you like and you'll get something that's hard to block, hard to dodge, and really puts the hurt on the opponent. According to the manual, Mahler is actually a completely separate character from B.M., and apparently bears a grudge against him. Who knows what the deal is there. He also wears poisonous-snake skin armour. If you want a really easy victory, then be my guest, and select him- you can play as him in any mode, including Arcade.

To Unlock: Complete Arcade Mode on VERY HARD.
That's Mahler on the left, and B.M. on the right. The difference is absolutely negligible, isn't it? B.M. is the final boss of Arcade Mode, and while the AI never really uses him to his full annoying potential on most of the difficulty settings, he's pretty irritating to fight against when in the hands of a human player, because he's slightly stronger than Mahler (we think?) and still has those brutal chain combos that will give you a pounding. Seriously, just whacking any button gets you results with this asshole. Don't play as him in tournaments, kids! As penance for his cheesiness, you can't play as B.M. in Arcade Mode- only Vs., Training and Team Battle.

Kumachan / Pandachan
To Unlock: Play 40 matches in any mode- Arcade, Vs., Team Battle, whatever.

I... What? What am I looking at? For the love of God, somebody tell me!

Yes, Kumachan is just as he appears- a gigantic bear. A bear that fights. With a cowboy hat. And creepy, creepy eyes. However, the true horror of Kumachan cannot be seen in mere screenshots, as he has no points of articulation- every single move that he performs involves no movement of his arms, legs, neck... He remains in his standing position, with his arms stretched out, as if he's just a toy being played with by a violently hyperactive 5-year old. As for how he plays, he shares almost all his moves with Sanman, with a few extra-powerful throws (including the dreaded Super Washington Treaty) and some strange spinning attacks added for good measure. Unfortunately, as he's a secret character, you can't see his moves in Training Mode. However, he appears as a standard character in Fighters Megamix, and so he gets names for his moves, including such exotic attacks as Kiss the Future and Poochy Acid Kick.

So who is this bizarre character, and why is he here? Well, Kumachan is actually in the original arcade game, seen in the background of Old Armstone Town (Bahn and Sanman's stage) as a giant statue. He appears to be a mascot of some kind, with the words 'ALL THE SINNERS SAINTS' emblazoned across his chest (SAD FACT: we had to buy the Fighting Vipers fan-book, ~My Sweet Honey~, to check what was on Kumachan's chest. Oh, the shame). Although not playable in the arcade version, he joins the brawl in the Saturn version, has his own protrait pictures, and has a second costume, Pandachan, who carries a giant beach ball (and also has her [?] own portrait gallery pics).

Next, let's take a gander at the Options Plus menu, where most of the game's secrets are kept...

Options Plus
To Unlock: Complete Arcade Mode on any difficulty setting.
Options Plus appears on the title screen, underneath the normal options in a grey font. The first time you unlock this, every version of the game (EU/UK/JP) has the Stage Select (pick your starting stage for Arcade Mode- if you use this, you can't record your time, and you can't use it to unlock stuff), No Damage (makes either Player 1 or Player 2 invincible- if you use this in Arcade Mode, you can't record your time, but it won't stop you unlocking stuff!) and BGM On/Off (switch the music on/off, duh) options unlocked. In the EU and JP versions, you'll also have Portrait (explained here) but this was removed from the US version because, uh...? In all versions, two of the options are locked away the first time you come here, whereas the Japanese version has a special mystery option underneath No Damage. The extra two options in all versions are...

Big Head Mode
To Unlock: Play 200 matches in any mode- Arcade, Vs., Team Battle, whatever.
A lot of sites seem to think that Big Head Mode is unlocked by 100 matches. This is wrong. Unless they changed the requirements for the US/UK version, it actually takes 200 matches before this finally opens up. It does exactly what it says on the tin- the characters all develop severe cases of Gigantism, and their heads swell up to ludicrous proportions. Actually, their feet and hands also change, so it's more like DK Mode in Goldeneye 007/Perfect Dark, and while it's incredibly amusing, it stops certain moves from working properly, screws up replays in the Playback Mode, and the graphics seem to flicker a lot more. Also, Pepsiman and Kumachan/Pandachan are, for whatever reason, completely unaffected by Big Head Mode. Still, it's a lot more entertaining than Virtua Fighter Kids, that's for sure...

Wall Display
To Unlock: Get 300 OKs in Training Mode.
You'll need to go into Training Mode to unlock this one- bring up the Command List, then perform a move correctly to earn an OK for it. If you're playing the Japanese version and can't read the special instructions such as 'behind opponent' or whatever, or you're struggling, pressing A or C while highlighting a move will make the computer demonstrate it for you. I'm not sure if it's exactly 300 OKs, but getting a full OK list for 4 characters ought to unlock Wall Display... Which almost certainly isn't worth the effort required to unlock it. All it does is remove the walls, to let you admire the backgrounds, and that's it. The walls may disappear, but you can still smash people against them, so it is, literally, pointless.

And now, miscellaneous stuff!

Clean Pause
To Unlock: Pause the game, then press X+Y+Z.
This is really useful for taking screenshots with. As I found out.

Change Armour Status Icon
To Unlock: Win 8, 16, 24 or 32 matches in Vs. Mode consecutively.
A completely pointless extra that takes more effort to pull than than it's worth, the Armour Status icon will change pose ever time you win 8 matches in a row in Vs. Mode (and, I assume, Arcade Mode) and that's all it does. Assuming your opponent sucks enough to let you win this many times in a row, though, getting to 36 wins starts the pattern from the default pose. Move along now, nothing to see here.

Pandachan in Intro
To Unlock: Beat Arcade Mode as Pandachan, then watch the intro.

Just as it says. Pandachan replaces B.M. in the intro when you beat the game with him/her/it.

I have nothing to add here.

Tokio and Kumachan's 5th Portrait Pictures
To Unlock: Uh...
Now here's a mystery, ladies and gents. I have no idea how to unlock these two pictures. Supposedly you can unlock the extra Tokio picture by beating Arcade Mode with Tokio after continuing 10 or more times, and you can supposedly unlock the extra Kumachan picture by beating Arcade Mode on the default settings without losing a single round, but I've tried both and... Nothing. I can't tell you how many times I tried to get these to work, and nothing.

Even better, the image above can only be found on the US and EU disc, and continuing over 10 times still doesn't work.

If anyone knows how to unlock these pictures, email me at TheMetalSlug at gmail dot com! I'm completely out of ideas.

As it was released internationally, here's the secrets to be found in the XBLA/PSN port of the game:

Mahler is unlocked from the start. Move left from Grace or right from Picky to select him.
Ranking Mode
Hold P+K+G and press Start while the Attract Mode is playing.
Random Mode
Hold Up and press Start while the Attract Mode is playing.
Kids Mode
Hold RB+LB (360) / L1+R1 (PS3) before adancing to the Attract Mode
Hold X (360) / Square (PS3) before advancing to the Attract Mode
Honey/Candy in 2nd Attract Sequence
Hold Up before advancing to the Attract Mode. Wait for the 2nd sequence to start.
Change Music on Main Menu
Press LT/RT (360) / L2/R2 (PS3) on the menu screen to listen to in-game music.
Destroy Honey's Skirt
Win 10 matches in a row in Offline Versus.

On the next page- Japan-only secrets. Don't show these to the kids!