I stated in the the BYOND Strategy rules that if you can't form plans then it's not a strategy game. Meanwhile, the original GrimTunnel design seems a bit too random. The game itself is deterministic (other than content generation), but the player actions are hard to account for.

I was planning on allowing GrimTunnel minions to use as much loot as was available at once and the effects would stack. However, this stacking makes the loot choices themselves less important. It becomes a question of how much people bought instead of what they bought. Why buy a expensive loot if you can use multiple copies of cheap loot? Why worry about negative effects from random loot if you can balance them out with guard or invade loot? Why worry about breaking locked loot open at any time if you can just toss it in with everything else? Why bother predicting what your opponent is going to throw at you if there was not any reason behind their decision?

I'm now thinking that it would be better to limit minions to one piece of loot at a time. This will make loot choices more important during the Shop phase in terms of both the loot's strength modifiers and the way the type of loot has to be used. Meanwhile, opposing players will be able to predict a smaller set of meaningful combinations... In other words they can form plans, at least in the short term.