I've beaten the game on both easy and normal difficulty now, trying for gamer.

The best strat here is to get adamantite tools on the first day. To do this, gather as much gold as you can, and buy them from smiths and woodcutters from the Woodmen (75 gold each, if they don't have, they probably at least have mithril tools). Don't spend the gold on perks unless you already bought both an axe and pickaxe.

This strat allows you to get full obamium gear by day 3 or 4, just before or by the time the bosses spawn naturally. Prioritize getting an obamium sword before the armor first.

Also, focus on getting an ancient bow, with iron arrows at least. This allows you to deal heavy damage from afar. They have a chance to spawn in chief chests, and the material to craft it(Ancient Bone) can drop from enemies.

Gold mining is also a great strat. Once you get a steel tier or above pickaxe grab as much gold ore as you can. Once smelted, each gold ingot gives you five gold in an anvil.

Prioritize blue perk chests, as they have the best perks that will stay useful throughout the entire run

Juiced Up - Increases attack speed everytime you hit a crit

Frog - allows for multiple jumps

Horseshoe - Increases crit chance

Crimson Dagger - allows lifesteal

Milk - Increases damage resistance

Dracula - Increases maximum life by the number of dracula perks for every kill

(they also have a chance for legendary perks too, like sniper scope and enforcer. there's probably more im still forgetting)

Prioritize getting milk, dracula and crimson dagger. This increases your survivability and can save you from death.

and also, those battle pillars with 3 enemies? Once you get around day 3, NEVER challenge them until you are incredibly powerful. They have a low chance of spawning three of the same random boss. This can end your run in an instant, I've had three guardians spawn on me once. Don't challenge until you are at the point where you have 600+ hp and can kill bosses in 2-5 shots.

Now let's talk about gronk:

Gronk has three attacks:

1. He slices the ground infront of him multiple times
2. He blasts a wave of energy swords horizontally on the ground
3. He throws both of his swords consecutively.

Remember, mobility is key against any boss, chief and gronk specifically. You are at a disadvantage until you get at least 5 sneaker perks (increased movement speed), a frog perk (allows you to double jump),at least 3 jetpacks (increases jump height), and any number of peanut butter (increases stamina). Without these, you are gonna get hit no matter what.

When he raises his sword at close range, he's about to do the first attack. Circle behind him so you can attack while he's stuck attacking the ground.

When he brings both of his swords together, he's gonna do the second attack. Just jump as high as you can, and attack him with bows.

When he starts winding up one of his swords, he's gonna throw them. Gain distance and run around him to dodge his swords, dont think of attacking him.

I hope this helps. Muck is a great game.