Alternative Strategy - The "War Of Attrition" Method
First of all, fuck this game and fuck this boss. While I often moan that modern games are too easy there is a big difference in a good honest challenge which pits player vs AI and games where half the battle is trying to cope with the shitty game mechanics and projectiles shot off screen.
The problem with me playing as Dorian and moving through the levels using the gun and spamming the jump kick (
) is that when I eventually reached the final boss, I was under powered and found myself unable to go toe to toe with him even using the other strats others have described.
However the strat I ended up using worked well, and I beat him after about 15 attempts or so. I would suggest switching off the woeful in-game music and perhaps putting on some of your own, or just avoid distractions in general. Note: This strat will take a lot longer to defeat the boss then the other strats described on this site (35 minutes in my case) so this is not for the impatient.100%-50% of bosses' health bar
At first, don't engage him, simply start sprinting clockwise around the edge of the stage whilst watching the boss carefully, it is important that you preserve the health packs so avoid breaking any of them as much as you can. If you sprint around the arena, the boss will rarely be able to catch you unless you are careless. When he throws his hat, you should avoid it just by sprinting but it is worth putting in a "safety" roll (
) to ensure the hat doesn't just nick you. When he smacks his arse, he will leap towards you and fireballs will fall from the ceiling. When this happens, just concentrate on just avoiding the fireballs and try not to stop and wait for them to fall before moving, as the boss' jump will put him closer and give him a chance to inflict some serious damage. The only time you should attack him is when he does his sprinting attack. If you are sprinting around, he will always miss and there will be a couple of seconds for you to hit him with a jumping kick (
) before rolling away and back to sprinting. You should inflict most of your damage with the gun, so when there is a healthy gap between you and the boss, unload on him. Note however, that your gunfire will break the health pots, and you may end up wasting a pack, so during this period try to only shoot south west. Note: In my successful attempt, I accidentally broke and collected the southern most health pack at full health. If this happens to you, it shouldn't cause too many disasters. In fact, it will give you a much wider angle in which to fire off your gun, which will make this stage quicker.50%-40% of bosses' health
It will take a while, but eventually he will start introducing his "purple" attack. It has a big AOE, so roll away to the furthermost opposite edge and wait for him to finish before beginning to sprint again. You might get slightly caught by this attack given the AOE, but if you have 1-2 of your health packs left you should be able to afford some hits.40%-0% of bosses health
Eventually he will start summoning his robot minions. Continue to sprint around the edge whilst keeping a sharp eye on them. You should be able to keep out of their range most of the time, however there is no way to completely avoid one of the little bastards taking a pot shot at you. this is why you need to switch your main focus to them, as the only clue you will have that they are about to fire is a visual cue. You can then block or roll away from the projectile. While each shot won't drain too much health individually, if you are sloppy then your health bar will be drained in no time. During this period your gun will become your best friend. About half energy will be enough to take out the robots and do some damage to the boss, or waiting for it to recharge to full energy will obviously take out the robots while taking a good chunk of the boss' health. When there are no robots, stop sprinting around and instead continue to sprint in a tight circle at about mid range from the boss. You are at slightly more risk from him getting in his combos, but you also want him to prevent him summoning more robots for as long as possible. When he leaps backwards sprint in and use the double jump kick (
) to knock him over, get two hits in and avoid having to deal with more robots at least for a short while. If he manages to summon them, go back to sprinting around the edge until your gun has enough ammo to take them out. Rinse, repeat and eventually you will defeat this bastard of a boss. The ending cinematic suggests there might be a sequel. Don't do it, Rimlight Studios! Just don't!
(Note: While there is a chance that all of the health packs may be gone before the final stage of the fight, if they are still there, I suggest using them in this order - south, north east and then north. This will give you a wider angle to fire your gun without worrying about wasting them.
Note: Even though the boss' health bar might appear drained, he actually has slightly more health than his bar suggests, so only stop fighting once the cinematic starts. I found this out the hard way in my 2nd attempt when I had thought I had defeated him, and had preceded to drop the controller and pump my fists in the air. The boss, still alive despite having no health strolled over to me during my moment of bliss and kicked my head in, So be careful.