Ring of Pain

Hello and welcome to my solution for Mastermind! This solution will also help get you the Master of Strategy Achievement, as long as you never equip an Epic or Legendary item.

Warning!: As with a lot of achievements in this game, it's very hard to predict how each run will go. My solution is simply the strategy I used to get both and it may take you several attempts in order to beat the run through. If you are not happy with how your run is developing by level 4 or 5, feel free to restart.

I started the game on Normal using the Double Candle and the Jar - Catalyst, as my chosen item.
I chose the Light Ending.

**Important Note! ---NEVER equip a Legendary (Gold) or an Epic (Purple) item! If you pick one up on accident you will have to start over. Only use Normal (Grey) and Rare (Blue) items. Only buy chests that cost 20 or 40 souls, NEVER buy or open chests that cost 75 or 160 Souls.

My finishing stats and equipment:

Health - 52
Attack - 30
Defense - 23
Speed - 45
Clarity - 16
Helmet - Cover of Darkness (Blue, Rare)
Torso - Living Corset (Blue, Rare)
Gloves - Cold Blooded (Blue, Rare)
Pants - Dark Pants (Blue, Rare)
Boots - Slippers (Grey, Normal)
Shield - Soul Charger (Blue, Rare)
Weapon - Soul Torch (Blue, Rare)
Mask - Chugging Mask (Grey, Normal)
Necklace - Infected Necklace (Blue, Rare)
Jar - Cycle through them to gain as many stats as possible.
Relic - Cash in (I used the Wishing Well once)
Gem - Cash in with Spellbook -Siphon Gem. (I ended with Thunder Egg - Blue, Rare)
Spellbook - Siphon Gem
Scroll - Cycle scrolls as they come along
Other decent options: Agile Boots, Supplement (Necklace)

General Notes:
You will end up with a lot of Souls by the end of your run, use them early to try and find the items mentioned above. Go after Scroungers aggressively, for those sweet skill points. If possible, think of explosives first in every room (after Scroungers), and how they can be used to safely kill your enemies (including Scroungers) or if they should be evaded. Cursed skill points should be picked up as often as possible, factor these into your strategy upon checking the room (up on the D Pad) when you enter each room. Sometimes tanking an explosion to damage nearby enemies can be worth it, but be careful. Use whatever equipment is available and cheap, until you start seeing Rare (Blue) items. Getting Chugging Mask and Siphon Gem (Spellbook) early can be very helpful, allowing you to boost health and focus on other stats. In the final 4 stages (after level 16) don't get greedy and get yourself killed by trying to get one last skill point; get out the door if you can, and leave the treasures and health if they are too risky to go after. Learn as much as you can about how each creature behaves, so that you have the best chance of predicting how each dungeon will go.

Rooms to avoid if there are other options:
Companions and Ravaged - a lack of skill points and multiple treasure make this less profitable than other rooms; although it's a good option for picking up souls
Patience - you must move to the exit quickly, not affording much time to pick through the room
Aggression - Gnashers are very tough
Ambush - only 1 item, which is especially unhelpful in the later stages of your run
Burial Grounds - good for souls early, if you can afford to lose some health but look for better options
Purple and Blue Vortex room with no name - useless
Shrine of Neglect and Shrine of Sacrifice - can't use items (they are Legendary, or Gold)
Chills - not horrible, but be very careful
A Quick Approach - Not bad but Lunging Spines can be tricky
Overwhelm - Not bad but some touch enemies
Dark For Days - skip ahead 1 full level... very bad, avoid at all costs

Good Rooms:
Reprieve - use as needed if you are low on health
Crossroads - always good to have options
Volatile
Reckless
Positioned to Strike
A Careful Maneuvre
Wishing Well - can cash in a Relic for some skill points
Fountain of Life - Good in a pinch

Here is a link to the Ring of Pain Wiki if you're looking for further information:
https://ring-of-pain.fandom.com/wiki/Ring_of_Pain_Wiki

I'm sure there are other setups that will work, so please list your suggestions in the comments. These runs can be unforgiving if you get unlucky, so I wish you the best of luck. I hope this was helpful. I have some sports videos and a few gaming videos on the YouTube channel: Preston Sports so let's chat sports and play some games. Thanks for reading and have a great day!

This is certainly the most difficult achievement in the game, but there are several strategies to be able to do it, and also unlock the "Master of Strategy" achievement.

A possible choice could be to do a run in inverted candle mode, taking advantage of the fact that you will not have to worry about ever increasing your speed, that you will start with excellent offensive and defensive statistics, and that in this mode the legendary items are definitely less relevant.

I personally recommend doing a normal run in candle mode, focusing almost exclusively on increasing the stats as much as you can. The best items to take are:
Catalyst (common), which will double the stat boosts;
Siphon Gem (rare), who will destroy your equipped gem making you gain its stats;
Any item with an high probability of intimidating opponents.

Last two tips:
Always try to kill the owl before the last dungeon, so obviously go for the dark ending;
Soul Spill is a truly incredible item, you will not use too many souls in this run and you will probably arrive to the owl with about 1000 souls, Unfortunately Soul Spill can only halve the life of the owl but it is still a considerable assist, if you can try to keep it until the end.

My guide for this is to start with the double candle and choose the Hermit's Tiara as your starting item. Being able to freeze enemies on hit will make you unkilliable as long as you get to attack first. This means that the few items you sould pick up (never have more than 3) should give you plenty of speed (like oil). You also want to build up a lot of clarity to gather as many souls as possible for the final boss (like a black opal or friend of frogs).
I choose to kill the owl as the freezing loop works on him as well in Reprieve. For his final form, grab a soul spill along the way, and since you will have many souls left over from not grabbing expensive chests, it should one-shot him.

Hope this guide helps