Gungrave G.O.R.E - Ganpo Boss Fight (Hard)
While I wouldn't consider Ganpo a mechanically difficult boss, he does a lot of damage, requires a lot more from players, along with being pretty cheap.
For the first phase the whole trick is to know what he is going to do. The first thing you need to learn is rushing doesn't matter. He will do that, decide to jump and you're going to get hit before you know what happened. As for his punches, lightning means he will stun, with the other one having a small delay after getting next to you. The former is okay to get hit with, though it often results in heavy damage, but the latter can almost one hit you with full shield and health.
As for the dreaded beam attack, this is avoided by running. Just dodge, hold down the dodge button and keep moving until it goes away. The sooner you realize the more damage you can do, though doing it early will result in considerable damage.
The other really annoying attack is his leap. The first two are timed so if you jump around the same time as him you'll avoid it, but the third has a slight delay where you need to wait for the circle. Dodging all three is pretty difficult, so if you can manage only one hit you're doing well.
As for the second phase, well, this fight just sucks.
The first lesson you need to learn is to slow down and watch his attacks. His laser, grab, and slam all look similar at the start, with the true attack being clear a moment or two after. Basically, you can get hit by the laser, just not the two other attacks. For anyone wondering, the laser can be dodged, it just requires a good understanding of how long it will take for the beam to hit you (closer is easier to dodge, but further is easier to prepare).
What ended up being the trick for me was abusing Hellhound. When firing you're completely invincible with time moving normally. This allows you to just ignore his triple beam at red health, while also dealing... well, it does damage.
For anyone who lacks Hellhound, saying no to the continue screen will boot you to the main menu. At this point you can select lab, purchase it and any other upgrades you might want, and then return to the exact point in the fight you were before.
At the end I had so many left over I attempted to just abuse it to make things easier. If you see him doing an attack, you can prepare to do it again and as long as it doesn't connect in the second or so between moves you'll be safe. I don't suggest it if you can consistently dodge his attacks, but it works.
Finally, for anyone wondering about 4:39, that was mostly luck. While it might be possible to break out of the grab on hard, something I was never successful in doing, he actually lets go of you a moment before the beam hits. Depending on placement, and where you're moving, it's possible to avoid it like I did without breaking free. I'd say it happened about 1:10 attempts, so possible, just not something I'd bank on.