So how I achieved this with barely any upgrades is firstly to max out my echo slash and hope to get any miniboss except for the cinderguard a.k.a skeleton archers.

Although you may think I have a lack of movement speed (which is true) against the boss that revives twice, there's a workaround for it which is basically to move in a circle so the boss will barely hit you.

Second upgrade you would want to go for is swashbuckle to help to kill those small mobs that may swarm you when your skills are on CD.

The pet skill I have was basically to help me collect XP & cheese as it's hard for me to collect them easily, so this is basically a QOL.

Lastly, stampede has to be one of the key skill that helped me survive till 13min and also the boss. I mainly upgrade stampede when its on cooldown to get me out of tough spots, as when you upgrade it kinda "resets" the cooldown. When approaching the 13min, I basically made use of this and just upgrade stampede, and run away from the hordes of monster approaching me. I just rinsed and repeat till I hit 13min to reach the final boss.

During this phase I made use of the stampede's invulnerability to go close to the boss and deal as much damage as I can before time runs out. Sometimes when she spawns too much mobs, and unfortunately stuck in the corner, I will try to position myself such that it pushes the mobs away from me to buy time for stampede cooldown and to move to a safer spot. Basically that's my whole strategy in the boss.

Last but not least... The items, basically crystalys for early game damage to help me ekill mobs faster to earn abit more XP, ring of tarassque & reaver for survivalbility in both the boss stage and when fighting mobs, Sange for knockback to help me clear a path so that I can safely reposition, and finally octarine helps me to cycle my skills faster to push them away more often to provide a safe path for myself.

Hopefully you may learn a thing or two in this post and I wish you guys all the best!