Exchange Machines are the key to winning consistently in this game. There are a number of items you can exchange for gems, but the most important option is exchanging Roses (the core upgrading material) for Gems (which you can use for buying items and core levels). The main quirk is that Exchange Machines only show up for the first couple stages, past Plantos you won't find any.

With this in mind the best strategy is to exchange all your Roses for Gems until you beat Plantos, Ignore all the Rose upgrades until later, this will give you a great power spike, as rose upgrades are usually not the impactful until the third tier. You will find plenty of Roses in the final stages to upgrade everything you want to.

Now that you're swimming in Gems you need to find something to spend them on. Your first priority should be looking at the highest tier food available, which is often the best option. Always take Extra dash charges if available. After that you should spend all your Money on Honk. Sophia is an option but only for the first stage, the only good Sophia Option is -50% Max Hp and +4 Max HP per Elite killed, the rest suck. Only take that option if you are confident you can kill the first boss with low HP.

Order Priority for Purchases at Honk:
1: Good Legendaries (Dash cooldown, Invuln Duration and others)
2: Immunities: Shock (100% required for final bosses) > Knockback > Freeze > Rest
3: Good Damage Reduction Items (% Reduction based on max hp, Reduction if used a skill)
4: Okay Legendaries (Sword, Reduced Burn/Poison Damage, etc)
5: Okay Damage Reduction Items (Reduced Projectile Damage, etc)
6: Everything Else

Core Level Ups:
If you don't get Honk and Food in-between stages you'll get a Healer and the Core Level-up Machine. This is different than Honk in that each level goes up by 300, after each purchase. The strategy is to focus on your main element, and upgrade the good scaling skills, especially the Legendary ones. Remember you can Reroll these choices if you have the correct Core reroll talent. You should never pay more than 900 on your main element, or 1200 if upgrading a Legendary. Always spend 300 or 600 Upgrading the frost talent for flat Damage reduction, if you don't the later stages will Destroy you.

Choose Lightning. That's it. The other two cores are awful in comparison. If you've beat the game with lightning you can try another core but they won't be nearly as good. Make sure you have the core reroll talent. Note that your rerolls are refreshed after every stage so you get something like 50 rerolls a game.

Always choose legendary talents if available, and make sure to reroll for them, especially at the end of a stage. Make sure you get the Lightning or Fire Hyper core as it does immense damage, and get a sub-weapon upgrade even if you don't use it, as there is a late game sub-weapon rose upgrade after you've finished your core upgrades. Otherwise there are a few core talents you need from every element so don't be discouraged even if you can't choose your main element.

Frost:
Freezing Dash (the best dash, it will save you a lot of HP in a run, dashes generally don't do much damage anyways unless you are the blade character)
Flat Damage Reduction (Essential in a run, always choose it)

Lightning:
Flat Critical Chance
Flat Crit Damage
Chain Lightning Spread (if you are maining a Lightning Core)

Fire:
Flat Damage (If you aren't Jenny) Otherwise avoid.

Toughness Cores:
These are very important, generally choose these over Elemental core upgrades unless it is your main damaging element. Reroll for 50 Max HP, though use the Max HP + Heal if you need it. You should End up with 600+ HP by the end of the game this way.

There are only 3 Talents you 100% need, the rest are preferences

• Dash Cooldown
  
• Core Rerolling
  
• Revive once after death

For the rest the generic ones that apply to all builds are the best in my opinion but feel free to experiment.

1. One level of the Core Lady (EO) on the Bottom Floor (you can give up and restart until you find your desired element)
2. Unlock Characters
3. Food Levels
4. Honk price reduction
5. Drones
6. Personal preference

I initially thought this game was too hard, but after some experimenting you can certainly win every time. The game is pretty fun in a similar way to dead cells, though the UI for mouse and keyboard is atrocious, and the dialogue poorly translated. At least you can rebind everything, which is a big plus.

If you are failing even with these tips it is likely a matter of experience or not enough Weapon/Meta-Talent upgrades. And remember if all else fails just play Jenny, her Gem weapon talent is the most broken thing that exists in this game. Good Luck. Drop me a comment if you disagree or have other suggestions.