Silver is probably my favorite game, but it's too easy, so I play with:

(All of this was done on the original, I'm not sure what's changed since that version and the GoG / Steam ones.)

No melee weapons
No special attacks
No shields
No ranged weapons
No orbs
No magic weapons / items
No potions

You can only punch, kick and dodge throughout the entire game, unless a situation calls for a specific weapon / item, in which case you must use the weakest weapon possible. For instance for the dragon in Spires you can only use the ice wand as you can't reach it unarmed. Also....

No gold farming.
No using more than 1 charecter at a time (all are completely unarmed at all times).
No hiding behind grandpa (you have to kill more than him in every room).
No ending fights early (you can only kill enemies that summon other enemies once they stop summoning enemies, unless they summon indefinitely in which case you can kill them at any point).
No skipping fights (like when the boy warns you the garrison is coming in Rain).
No skipping bosses (like the yellow imp).
No skipping areas (if there are 2 paths to the same place you must go down both paths).
No easy options (you cannot buy silver for the werewolf or use the fairy ring near Davids house).

Certain bosses have certain rules, for example:

On the 2nd boss you can only attack after 2 imps have spawned and you kill them both (unarmed) before the boss begins summoning again after you kill the first one, only then can you attack (once) with the ice wand.

For the fire alien boss you can't attack the boss (with the slingshot) if there are any blue aliens, you have to kill them (unarmed) before you can attack the boss.

For the dragon in Spires you can't get hit. You are allowed to get hit, but because you're using the ice wand it's a long fight, getting poisoned is simply not an option.

For the ice dragon I did manage to "beat" it using the short sword, but once 100% of its life bar had gone it didn't die, I kept hitting it but it wouln't die. I think it bugs unles it takes magic damage, so you'll have to use the fire sword (melee, not ranged).

Bosses like the ice viking and minotaurs have no rules, you just beat them however you can.

There are a few parts in the game that stand out, namely:

1a) The 2nd half of the library of Gno when flying and brute imps start appearing, followed immediately by...
1b) The "golems decent" under the library of Gno, mainly the room with 4 golems and the imp that ressurects them.
2) The werewolf in Rain.
3) Any boss that needs a ranged weapon to kill, they become endurance fights (dealing 1 damage per hit).
4) Cagan. He deals MUCH more damage with unarmed attacks (30+ in comparison to Davids 1 - 6).
5) Fuge. Undoubtably the hardest part of the whole game, I can't beat him without using potions, he's as far as I can get on this difficulty.

Apart from using potions on Fuge I managed to make it all the way to Deadgate by following these rules, and the only reason I didn't make it further is because I messed up and didn't save enough gold for the trip, instead of going back to an earlier save I thought I'd start again and try to beat Fuge without using potions this time.

The trick is beating bosses in the right order, beating the easier bosses will give you better stats for harder bosses (such as killing the fire alien before the werewolf). Also using save points correctly is important, you'll likely want to restock before saving which sometimes means going to a different area to kill enemies for food and gold, do this in preperation for the next area BEFORE you save (unless you just beat a boss or hard part of the game). Once you make it past the burning forest pass David isn't a viable option anymore, you'll want to go and get Cagan before doing anything else.

It's really not *that* hard, there are only a few parts of the game where it becomes really hard, but 90% of the game is just stun-locking everything with constant kicks. If you loved Silver but thought it was too easy, I'd try out impossible difficulty haha.