The power provided by Hexslinging is fickle, and prone to blowing up in the user's face. That's the price you pay for forcing evil spirits to do your work for you. Casting a hex requires a mental battle with a Manitou; while this takes just a second of real time (a Concentrate action), it is still a complex mental battle and a gamble every time. Hucksters who follow Hoyle's teachings use poker as a mental framework for the magic. One of the side effects of this is that a hand of cards appears in the Huckster's hand as he casts the hex; when he releases his will to cause the effect, he must look at the hand to see if he's won. This is fairly obvious to onlookers, but can be concealed with a Holdout roll (use a Quick Contest of Holdout vs. Perception if an onlooker is specifically watching for such an effect); the roll is at +4 if the Huckster is actually holding a deck of cards.
All Hucksters must have the advantage Arcane Background: Huckster (An Unusual Background) costing 5 points. This allows them to buy the Hexslinging skill (IQ/VH, no default) and to get powers with the 'Huckster Hex' limitation below. Finally, there are some advantages only available to Hucksters; see Deadlands\New Advantages:
In order to successfully cast a Hex, you must succeed on a roll against the Hexslinging skill; this is a -5% variation on Unreliable. All Hexes also have the Source: Magical limitation (Powers p.27) and involve Backlash (Powers p.104): on any critical failure of the Hexslinging skill to cast a Hex, roll 3d on the Backlash Table below; this Backlash is a -15% limitation.
This overall gives all Hex powers the limitation 'Huckster Hex', worth -30%.
Additonally, nearly all hexes cost FP. Afflictions and Maledictions cost a minimum of 1 FP per level, and Innate Attacks that are affected by DR (non-afflictions) cost a minimum of 1 FP per 2 dice. GURPS Magic is a useful guideline for pricing other hexes. Minor effects (any Perk or other minor effect, subject to the GM's judgement) may cost no FP. See, however, the below option for Dealing with the Devil, which imposes a greater risk of Backlash but can provide free FP to power hexes.
Hexes are NEVER subject to the rules for Alternative Attacks or Alternative Abilities. Each one is separate. Them's the breaks.
The Hexslinging talent (10/level) adds to Hexslinging rolls and other Hex-based skill rolls (including Innate Attack and those for normal gambling) and provides a bonus to reactions from manitou, gamblers, and other Hucksters.
Corpse Light: Accessory Perk (Lantern) (Huckster Hex, -30%) .
Notes: This generates a sickly green light roughly equivalent to that of a lantern; the glow doesn't have a specific source but is centered on and moves with the Huckster.
Devil's Grin: Charisma 2 (Huckster Hex, -30%; Costs 2 FP, -10%) 
Notes: They say the Devil's a charming sort, and a bit of it has rubbed off on this Huckster. This Hex confers 2 levels of Charisma when activated, providing +2 on all reaction rolls the Huckster makes for the duration. It costs 2 FP to activate for 1 minute and can be maintained at 1 FP/minute.
Shadow Man: Invisibility to Electromagnetic Vision (Huckster Hex, -30%; Costs 4 FP to activate, -20%; Visible Shadow, -10%) 
Notes: The Huckster vanishes in the blink of an eye, becoming invisible to any onlookers, though the clever among them will notice he still casts a shadow. Shadow Man costs 4 FP to activate and can be maintained for 2 FP/minute.
Card Sharp: Innate Attack 1d cutting, Acc 3, Range 25/50, RoF 5, Rcl 1 (Huckster Hex, -30%; Reduced Range 50%, -10%; Increased 1/2D Range x5, +10%; Rapid Fire (ROF 5), +70%; Costs 2 FP, -10%) 
Notes: The Huckster manifests a hand of eerily glowing playing cards which he throws at the target, inflicting cutting damage. This hex is not subtle! Use Innate Attack (Projectile) to hit.
Soul Blast: Innate Attack 1-6d toxic, Acc 3, Range 200/1000, RoF 1, Rcl 1 (Huckster Hex, -30%; Increased Range x10, +30%; Increased 1/2D Range x2, +5%; No Signature, +20%; Variable, +5%; Costs 1 FP per die, -15%) 
Notes: One of the trademarks of the Huckster (and one of the reasons many of them get burned as witches), this is a direct assault on the vitality of the target. The faintly glowing 'blast' is all but invisible; in any light brighter than a half-moon, opponents are at -4 to dodge. In the dark, it can be seen as a faintly glowing trail traveling from the Huckster's outstretched hand to the victim's heart. Use Innate Attack (Projectile) to hit; if the victim is actually killed by this Hex, the flesh dries up and flakes off their bones, leaving only a well-polished skeleton behind.
Helpin' Hand: Healing (Huckster Hex, -30%; Preparation Required (10 minutes), -30%; Based on Hexslinging instead of IQ, +20%) 
Notes: The Huckster must spend ten minutes quietly playing solitaire poker in order to make this hex work; if he succeeds on his Hexslinging roll, he may spend any number of FP to heal the subject, who must be present during the preparation time.
Phantom Fingers: Telekinesis ST 10 (Huckster Hex, -30%; Costs 2 FP, -10%) 
Notes: Allows the Huckster to manipulate objects at a distance as if using his own hands. Costs 2 FP to activate for 1 minute; can be maintained for 1 FP per minute afterwards.
Dealing with the Devil
While dangerous, some Hucksters are desperate - or foolish - enough to take this option. As a hex is cast, the Huckster can decide to try to gamble for more than just magical ability; he can try to force the Manitou to power the ability as well. The Huckster declares how many FP he needs, including those to pay any upkeep. Draw 5 cards, +1 card for each level of Grit the Huckster possesses, and compare it to the following table (aces are HIGH):
Pair: 1 FP
Pair (Jacks or higher): 2 FP
Two Pair: 4 FP
Three of a Kind: 6 FP
Straight: 8 FP
Flush: Provides all needed FP for the effect.
Full House: Provides all needed FP, and boosts the hex's power in some minor way - +1-2 damage for attacks, or something else appropriate.
Four of a Kind: Provides all needed FP, and boosts the hex's power in some significant way - +2 damage per die for attacks, or something else appropriate.
Straight Flush: Provides all needed FP, and boosts the hex's power considerably - double damage for attacks, heavily extended duration, or double other effects.
Royal Flush: Provides all needed FP as Straight Flush, and intimidates the manitou; the Huckster gets an extra card on all attempts to Deal with the Devil for the rest of the day.
Backlash will occur when Dealing with the Devil in three cases.
Fail the Hexslinging roll: Any failure (not just critical failures) on the Hexslinging roll will trigger Backlash.
Use a Joker: Jokers are wild, and virtually guarantee a good enough draw to power a hex. However, if a joker is used in the final hand, the Huckster suffers Backlash. This MAY cause the Hex to fail, or hit a friend, but will not always do so - unless some other factor occurs, the Hex will go off.
Draw Low: If the Huckster fails to draw a high enough hand to power his hex, the Hex fails and he suffers Backlash.
When Dealing with the Devil, the Huckster MUST gain all FP for the Hex from the draw; he cannot spend his own FP to aid in casting or maintenance. A Huckster may not use Dealing with the Devil to get more FP than his personal maximum. Excess FP are lost; if you only asked for 2, and got 8, you still only get 2.
Whenever a Huckster incurs Backlash, roll 3d on the following table; in ALL cases, any FP spent for the hex are used up. Note that a bad hexslinging roll or a poor draw when Dealing with the Devil CAN turn 'works normally' into a failure; this still has any other consequences listed for the backlash:
3: Hex fails entirely; Huckster loses 1d HP and 1 point of IQ. Roll IQ every 24 hours; success returns the lost IQ point, critical failure means the loss is permanent.
4: Hex targets the Huckster (if baneful) or a nearby foe (if beneficial); if there is no nearby foe for a beneficial Hex, it simply fails. Huckster also loses 1d HP.
5: Hex targets a nearby ally (if baneful) or a nearby foe (if beneficial); if there is no nearby target, the Hex simply fails. Huckster loses 1d HP.
6-7: Hex targets the Huckster (if baneful) or a nearby foe (if beneficial); if there is no nearby foe for a beneficial Hex, it simply fails. Huckster loses 1 HP. 8-9: Hex targets a nearby ally (if baneful) or a nearby foe (if beneficial); if there is no nearby target, the Hex simply fails. Huckster loses 1 HP.
10-11: Hex works normally; Huckster loses an additional 1d FP.
12-13: Hex has the reverse of the intended effect; a Soul Blast might heal the target, while Helpin' Hand might cause him to bleed out. Be malevolent!
14-15: The Hex works normally, but warped magical energies mess with the Huckster's karma; he loses any remaining Fate Chips. If he has no remaining Fate Chips, he instead gains Unlucky 1 until the end of the next game session.
16: The Hex fails; the Huckster immediately loses 1d FP and must check for Knockdown and Stunning as if taking a Major Wound.
17: The Hex fails, and magical backlash wracks the Huckster's body; he loses 1d FP and 1 point of HT. Roll HT each day to recover the lost point; critical failure means the loss is permanent.
18: As 17, but the FP loss is 2d and the Huckster immediately falls unconscious. Roll HT each sunrise or sunset to wake.