I haven't tested this yet, but a potentially interesting variant would involve gaining a power token at the beginning of every turn if you have a pact and having to spend a sanity or stamina for it (if you have a blood pact or soul pact). If you have neither, you can't spend them, even if you have a bound ally.

I might actually be willing to play with everything else in Lurker as normal (except for discarding all power cards during final battle) with that rule. I'll give it an experimental go soon.

Sounds interesting - definitely makes you reconsider grabbing a pact and once you have one, makes it more costly.

On a related note, here's an idea I'll be trying soon. I thought of this after my last game with the Lurker was a cake walk, even with limiting how the power could be used (can't spend at once, power is bound to pact used to gain it).

Basic idea: when an investigator gains a blood or soul pact they begin to lose some hold on reality due to the Lurker's influence. In particular, there is the possibility of:

• Reality slipping away: The investigator can no longer pick up clues from the board (they may still gain clues by other means such as encounters, dissection at the science buildings, reading tomes).
• Memory loss: Every time the investigator gains power from draining stamina or sanity, they must discard a matching number of clues (if able). For example, if they have 6 sanity and two clues and use a soul pact to gain three power by draining sanity, then they lose both clues).

The way these come into play:

• The first time an investigator gains a soul or blood pact, select "Reality Slips Away" or "Memory Loss" and apply it to that investigator for the rest of the game.
• If an investigator has both a blood and soul pact, then both items apply.

(Alternate: bind each effect to a particular pact, say "Reality Slipping" away to Soul pacts and "Memory Loss" to blood pacts)

These are designed to be added to the "can't use power the turn you get it" (however you choose to interpret that) and "must discard all blood and soul pacts at start of final combat".