Sledgehammer might be the first d100 system that I would recommend with absolutely no reservations.
It's two pages total, including both a GM and player document, and it has a fun and extremely readable hand-lettered and illustrated visual style.
Mechanics-wise, it's direct and simple. You're trying to roll d100 under one of your four stats, and adding bonuses for any relevant backgrounds or equipment.
However, to negate the swingyness of d100 systems, when you get into combat, every time you deal damage or create an opening you increase your odds of hitting. This gives combat a sense of continuous acceleration.
Damage is still pretty swingy, with your tens die determining how many wounds you deal (5 is your max, unless you take corruption to get to 6), and there's hit locations and critical damage rules to make things even more potentially brutal. So this is probably not a system where you get *extremely* attached to your character, but there's also neat progression rules if you do stick around.
For GMs, there's some short but solid advice sections and some potential NPCs, but Sledgehammer feels like it's so easy to write for that bashing together a scenario or borrowing a scenario from another d100 fantasy game wouldn't be any burden.
Overall, this is a well-made, easy to use thing with a clear aesthetic and strong mechanics. If you want to tell a mud-and-blood fantasy story and don't want to finely machine together a complex statline to do so, Sledgehammer should probably be your go-to.