During the fifth chapter, I mainly used Tornado, so the skill sets are based on that. Also, I always spent gold coins on weapon and armor scrolls when the merchant had them, which is 12000 gold for 10 armor scrolls and 18000 gold for 10 weapon scrolls. Therefore, I always try to keep around 18000 gold on hand.
Useful Tips
Invincibility is the most overlooked skill. Before heading to a new location, stand at the entrance / exit. Wait until the invincible shield appears. As soon as it disappears, count out 6-7 seconds, and then go to a new stage. When you enter a new room, the shield will be on for the first few seconds. This is extremely important as you will most likely take more damage during the first few seconds when all enemies are targeting you.
If you have the Pierce skill (aka Tornado), avoid the ricochet, as during it your damage spreads to several enemies - accordingly, it will be much less. It is better to concentrate forces on one enemy and quickly kill him than to run and weaken several minions.
If you have +1 Forward Arrow, do not stand too close to a wall or obstacle as they will absorb your attacks. And if you have already chosen Front Arrow +1, do not use the second one, because your attacks will be less effective.
When using Tornado, always try to attack in such a way as to minimize the distance between the enemy and the wall / obstacle.
To escape the melee minions, grab at least one Ice Attack / Ball / Sword along the way.
Prefer the +1 Diagonal Arrow over the +1 Side Arrow.
Common enemies
Laser Bits: First aim at you and then shoot the laser in a straight line. Let them focus and then step aside.
Purple Electric Spheres: a swift attack of two balls, between which electricity flows. Dodge and attack.
Skeletons: are constantly harassing you, so keep your distance and get rid of them as quickly as possible. Don't let them corner you.
Arrow Turrets: Like lasers, these enemies aim first and then attack. The difference is that turrets can shoot diagonal arrows. They don't just attack you with one straight arrow, they shoot two more diagonally! So, have the turret focus on you first and then step aside and look for a safe gap between shots.
Stone elementals: they are back, but now the elementals are spinning like a tornado! They also attack with projectiles in any direction, so just dodge them.
Magic braids: These are essentially the same pets that you can collect in the game. They chase you quickly and do little damage. Move as fast as possible and try to destroy them as quickly as possible 
Red Crystal Turret: Similar to the Electric Tower you fought in the past, but instead of throwing lightning bolts, it releases a circle of fireballs. It's not that hard to dodge them, and the turret doesn't move.
Dogs / Wolves: Melee monsters that appear randomly on the map. Just try not to get in their way. I recommend the scythe as a weapon.
Bosses
Gray wolf: As soon as they jump attack, step to the side and do 3-4 hits. For beginners, I recommend only hitting 1 hit.
Green Archer: Step aside and avoid crosshairs.
Flying pig: Keep your distance and hide behind walls. Watch out for any attacks in the direction of the X and Y axis. As soon as the boss turns to face you, immediately step aside.
Plant: I usually restart this boss if my skillset is not very good (just close and reopen the app). Once the plant shoots a big red ball at you, don't run sideways - instead run slightly diagonally. Because if you run horizontally, the big red ball will explode and damage you. If a small plant appears near you, kill it. If it's far away, ignore it or try attacking from a large plant.
Fire Demon: just keep your distance from him. It shoots a direct blast of fire, which is easy to bypass and then immediately attack.
