Mini Six is a game I've had for a number of years now but never had the chance to use. I really like what I've read and it seems to get praise online, but one complaint I've seen repeated multiple times is that the magic system is a bit broken. For those that have used it, what's your take on the magic system? To my inexperienced eye the target numbers really seem to be all over the place, but aside from that nothing jumped out at me as being too out of whack.

I didn't come up with this, but I did format it up in its current state; it makes magic significantly more freeform, which I think the system really works better with.

Mini-Six Simpler Magic System

The devs themselves say it was rushed and almost as bad as a placeholder magic system.

As Steve mentioned a more popular magic system was fan created and called Simpler Magic System. 

Basically, the player describes what they're trying to do, and the GM sets the target number for that attempt.

Example.  I want to use telekinesis to bend a spoon I'm holding.  That's very easy.  Target Number is 5.  Then I want to lift a battleship out of the ocean and set it on shore from miles away.  That's going to be very hard.  Target Number is 35. 

It might even change from scene to scene for the exact same task.  Why?  Because magic isn't logic.  It's unknowable, so sometimes it does that.  Or the GM just needs it to not work so the scene plays out as intended, because magic can solve problems too easy.  Just don't do this too much because magic is meant to be useful.

Also, I created a different version of that Star Paladin's "Sense Danger" power in the back of the mini-six book for Imperium in Revolt setting.

Basically, you activate (Target Number of 5 per Enemy) and maintain you power and turn your plasma sword into 75% cover (+10) vs ranged weapons. Also, if an enemy rolls a 1 on the Wild Die, the shot is deflected back and hits the shooter automatically even if the shot would have hit. 

If you roll a 5-9 to activate the power, you will be protected from one enemy.  If there are actually four enemies shooting at you, baddie 2-4 will not suffer a +10 to their shots to hit you.  If you roll a 25, only a sixth baddie gets to shoot normal.  Only a roll of 1-4 is a failure.

It's useless against melee attacks. 

That's because nobody play tested the Sense Danger power.  Lowering offense by 1D6 (concentration penalty), while raising defense by 2D6 means two paladins using the power almost can't hit each other.  Ever.  So I changed it to ranged defense only, not impervious, easy to activate, and auto hits on the Wild die so it's worthwhile to use instead of literally taking cover.

I used Mini Six with the magic system for a Primeval Thule campaign. I thought it worked very well, I don't grok why people complain about it. Spellcasting was powerful but not OP.

https://simonsprimevalthule.blogspot.com/2020/01/the-valley-of-scorn-palace-of-silver.html

Thanks for the replies. My first instinct is to try the RAW magic rules just to see how they go, but it's good that there's an alternative if issues crop up. And I'm glad at least one person has used the basic rules without issue. I can see the attraction of a more open system, though.

Another option for magic for Mini Six are the Epic Mechanics/Aeather Feats in the Breachworld RPG, which is based on Mini Six.  They're essentially magic spells.