Brotato

Like TTV Aerico34 said in his guide, turn the enemy health/speed/damage down to 25% and this'll be a breeze.

I've found the easiest class to take for these is pacifist. I was able to get through Danger 5 without lower the difficulty only dying twice with this build. Basically you just turn yourself into a dodgy tank and run around until the level is over. Once you have sufficiently high HP Regen (3+ hp/sec), Dodge(60), Speed(20+) and Armor(10+) you're pretty close to invincible. If you get Adrenaline...you might actually be invincible.

Don't take anything that increases attack in any way. In fact, because you can just keep dropping your attack stats, there are tons of items with literally no downside.

Weapons
Hand - This is all you need. Damage doesn't matter, but the knockback is amazing.

When you level up and can choose stats prioritize them in this order.

Max HP - You'll only need about 75 at most, but I've had runs upwards of 150.
HP Regen - If you can get this up to 3-4 hp per second along with the other stats I'm recommending any damage you take is recovered very quickly.
Dodge - You want to max this out at 60.
Armor - You want this up around 10 at least. The higher it is, the less damage you do take when you're hit.
Speed - This should be at 20 or higher by the end of your run. I tend to take this early up to about 10.
Luck - If all else fails, this isn't a big deal to take.
Attack Speed - I've never found it necessary, but it's the only other stat that will actually help you.

Don't take anything else, especially range. The lower the range, the better with melee builds because it increases the effective attack speed.

Items
If you don't have enough for this, lock it. Sell stuff if you have to, but get this.
Adrenaline - With max dodge and high armor this makes you effectively invincible. With as much dodging as you do, even if you do take damage, the health regen on this will recover your health almost immediately.

Always Take (If your dodge is at 60 you can pass on +dodge items)
Beanie - Increases your speed and your effective attack speed by decreasing your range.
Blindfold - Dodge and attack speed again.
Blood Leech - Keep an eye on your harvesting and make sure it isn't in the negative, but this is helpful.
Boxing Glove - Increased Knockback
Cake - Free HP
Cape - Huge bump to dodge. (Every time I've seen this, I've already been maxed out, so if you're at or near 60 dodge, you can pass on this.)
Chameleon - Added dodge
Coffee - Attack Speed ++
Extra Stomach - This is a great item and if you have a bunch of trees/gardens you can ramp up your HP very quickly.
Garden - Healing
Grind's Magical Leaf - Just don't take this between rounds 19-20 as it's useless, but even one bump to HP and regen is helpful.
Lemonade - Better healing
Lost Duck - Better Luck
Lucky Charm - Same as the duck, but more.
Medal - Pads several key stats
Medikit - +10 HP Regen is huge and on 60 second levels it'll be at +34 by the end of the level
Metal Plate - Free Armor
Panda - Great for added luck, plus some HP
Peaceful Bee - Dodge plus some cash via harvesting
Piggy Bank - Lets you stack cash and makes the later levels almost inconsequential if you play it right.
Potato - Just a bunch of good stats.
Propeller Hat - Free Luck.
Schmoop - HP Regen!!!
Tardigrade - If you manage to get like 3 of these, you can make it through most levels without taking damage when you have maxed out dodge.
Tree - Always take these on any build. They're never bad.



Take in Early Rounds (Before 10 or 11)
Coupons - Cheaper stuff
Dangerous Bunny - Free rerolls add up fast
Fertilizer - Good for extra cash
Tractor - Good for extra cash


Can be effective if you have extra cash
Cyclops Worm - Damage is useless, but the reduced range is good.
Head Injury - Same as the worm, damage doesn't matter, but reduced range is good.
Scar - Free xp (I never really needed it, but it's beneficial for sure.)
Terrified Onion - Good way to bump speed if you need it, just keep an eye on your luck.
Ugly Tooth - Slows enemies down. It's so so and loses it's effectiveness if your speed is above 20.
Warrior Helmet - +3 armor is awesome, but make sure you have high speed before you do this.
Wings - If you need speed, this is good, but at the expense of lower range (faster attacks)

If you don't want to cheese this with changing the settings, I would recommend the Engineer.

For damage, prioritize wrenches, turrets, and the engineering stat. Basically I would try to get as many turrets as possible as soon as possible. Combine wrenches if you can to get another slot open whenever you can if there is another wrench for sale. The trees to turrets upgrade is great for this.

For survival, prioritize max health and armor. If you're not great at maneuvering I would also get some dodge as well. If you don't come across a health turret you will definitely need some health regen. Honestly, if you not great with avoiding damage I would almost say it is necessary and it allows you to stick around your turrets which is nice instead of chasing consumables for health.

Don't be afraid to restart early if you're not getting good rolls. Things get pretty hard around 10-12, so you may be able to squeak by for a few levels, but if you're struggling you won't make it that far. This compounds with the fact that you're getting less materials if you're killing slowly, so you will continuously fall further and further behind.

Honestly, I just did this very easily with Knight without turning down the settings.

Just build heavily into survivability. Armor/dodge/hp/regen plus cute monkey and you'll be practically invincible. Plus, since knight gets melee damage from armor, you get a substantial passive damage bonus.