Some, usually at the behest of RetroAchievement sets or out of boredom.
I guess a more interesting response comes from my speedruns of Mega Man Legends; several challenge runs have categories on the category extensions board on SRC: https://www.speedrun.com/mega_man_legends_category_extensions
Perhaps the most challenging were my Busterless & Low% runs.
Busterless is what it says on the tin: beat the game without ever using the Mega Buster. This sounds straightforward on the face of it, but to bypass the early game you are left with so few resources. You have to KICK the first boss to death. The next bosses are straightforward enough, and then you get to City Hall. You only can use land mines, in a limited quantity, to hit flying enemies. If you line up the Hornisse right, though, you can explode your own mines and just barely hit them.
If you kill them all without running out of mines, the remaining enemies can be beaten with kicks (even Bon, if you're careful and manipulate his position). Afterwards the game is straightforward since you'll have access to the Machine Buster or Grand Grenade soon enough. (Maybe one could be safer, e.g. Shining Laser, but since it's in a speedrun setting I also want to go somewhat fast, and Grand Grenade does the trick. Though even the route I did was considerably safe.)
My run: https://www.youtube.com/watch?v=C_q--EJxw30
A proper run by BlueMetal, the game's main runner: https://www.youtube.com/watch?v=UxF3FNYd88g
This I considered the hardest challenge I did for a while, tbh.
But last month in the same game I finished the game with the fewest items known possible ("Low%"). (I had done Low% before, before I realized one more item could be cut off.) This ended up meaning the use of a few glitches and getting kinda lucky at several points. The boat battle is so difficult because you have no Range on your Buster, and so you're stuck with 16 Powered Buster shots to kill Balcon Gerat's cannons and laser - wiggle room of one shot from perfection, but explosion damage is RNG-dependent. You can hit the arms with the Buster (which is only at +1 Attack), but only barely. Most attempts died to just the ship being hit too much.
The second time out of 27 I managed to get past him, I succeeded though. The air battles were also scary (similar situation - I was 1 hit from dying) and the sub-cities (no armor or healing means the Sharukurusus hit like a BUS). The final boss ironically has an invincibility glitch to exploit though.
My run (some more details in the description): https://www.youtube.com/watch?v=Z4DRmB82PGo
(she/her) | Math nerd, lover of pineapple on pizza <3
Infodumps:
Dark Cloud 2: https://is.gd/PSE06J | Pokemon MD: https://is.gd/1lK5bM