Here are my strategies for the bosses including my Video completing Boss Rush Mode. As you can see I made it to the last boss with almost no damage , but almost didn't complete it due to 2 poorly timed jumps on the last boss.
Boss 1The caterpillar boss has a very set pattern and its easy to memorize. Stand just forward under the left platform. Strike once , then jump on top of the platform. Drop down and slash 2 times. Repeat this process one more time. Once the boss goes off screen jump on the right platform as close to the right edge as possible. Once the boss comes down jump and slash 3-4 times. Now go to the left platform and stay as close to the left edge as possible. Once the boss comes down jump and slash 3-4 times. He should be dead after this.
Boss 2As soon as the boss fight starts hold left. Once you can control your character jump over the boss to the right. Slash him 2 times (No more than 2 times) then run all the way to the right side of the screen. As the boss charges you jump over him. Slash him 2 times then move a few paces left of him to avoid his attack. After this move back to the boss and slash 2 times. Run all the way to the left of the screen and do the same strategy as above. The bosses pattern and strategy doesn't change.
Boss 3As soon as you reach the bottom space yourself so that your sword slashes are hitting the first spot on the right , after 4 slashes it will be destroyed. Next you want to position yourself just to the right of the second turret. Keep slashing until it is destroyed. As soon as its destroyed you must jump up to the floating platform. Keep jumping up and slashing 3 to 4 times either side of the last target making sure to avoid the laser below you. Its difficult to explain , but very easy once you watch the video.
Boss 4There is 4 platforms during this boss fight. Jump to the 3rd platform. Face left and keep slashing over and over. You will see a read laser aiming down at you. Once the laser changes to a solid line jump to the left to the 2nd platform. Face right now and keep slashing. The boss will now shoot missiles. Keep standing facing right and time your jump so you can jump up and destroy both missiles at the same time. The boss will do this twice. Now keep slashing until the red laser appears again and then once again jump over to the right once the laser goes a solid red color. A couple more slashes and the boss will be dead.
Boss 5As soon as the fight starts go to the very left of the screen. The boss will either charge you in the corner or at half screen will start his attack. Wait for him in the corner and jump over him. You must now use the opening to attack him , so jump and slash him , then jump over his attack and slash 1 time. Next move a little in the opposite direction but not far enough to be half screen distance as he either attacks left side , right side or in the middle. Keep moving in the opposite direction jumping over him and landing a few slashes. He goes down pretty quickly so don't expect to have to do this for more than 2 to 3 times.
Boss 6Start the fight by jumping to the very top branch on the right and slash as many times as possible. The branch would always break for me before the snake boss would shoot fire. as soon as the branch breaks hold left and go to the left branch one up from the bottom left branches. Also make sure you are on the very left side of the branch. Keep jumping here until the fire is gone and then jump back to the top repeating the process. This is a very easy boss fight.
Boss 7As soon as the fight starts jump on the right hand, then jump up and slash the boss. Fall down back to the right hand and jump back up slashing the boss , this time landing on the moving platform. Once you are close enough jump to the left hand and now repeat the process by hitting once , falling back to the hand , then jumping quick and slashing again before falling on to the moving platform. Once on the platform stand on the very right hand side to avoid the lasers he shoots down. After a few slashes he will blow up revealing a small man at the top. He shoots grenades but the strategy remains the same.
Boss 8As soon as the boss fight starts jump and slash 2 times , then jump and hang on the hanging platform to the left. By doing this you will make the boss come directly towards you. As soon as he approaches drop down. Now chase him by jumping and slashing up to 4 times. Jump back on the hanging platform again once the boss stops in the middle of the screen. As long as you are on this platform he will always shoot his balls starting from top to bottom , left to right. As soon as he starts shooting drop down , run under him and jump on the hanging platform to the right , then jump up top and move to the left side of the screen. Drop down and slash 2 times. Keep doing the above strategy and the boss will die within 2-3 transitions.
Boss 9This is one of the toughest bosses, however there is a way to get him in a sort of loop. As the fight starts run towards him. As soon as you are close enough to hit him with your sword
SLASH ONE TIME , then change direction and again as soon as you are close enough to hit him
SLASH ONE TIME. Keep doing this over and over from side to side. If you notice he jumps back , be ready to jump over him. He also has another attack where he will jump to a hand rail on either side and throw grenades down at you. Wait for the grenade and jump over it , then jump up and slash him 1 time. He throws 3 grenades so after the 3rd one run back to start the process again. Once you think you have him beat he will enter RAGE mode and the fight will start again. Follow the same strategy as above as nothing changes other than the damage he does and his slashes go a further distance. If he stops the loop and starts slashing multiple times back off by jumping in the opposite direction , then start the process again. Another tip is DO NOT JUMP in this fight as it removes the loop. This is the toughest fight in my opinion of the whole boss rush.
Boss 10This boss can be very easy or very difficult depending on what he chooses to do. As soon as the fight starts move to the center of the screen. The boss dissapears and reappears to slash 3 times.As soon as you see him appear take a few steps to the left and turn around and slash him 3 to 4 times. Sometimes you get lucky and this is all he does for his first phase,however if he appears in the middle of the stage and starts levitating(moving up) , then you need to jump and slash him 2 times. He will now shoot large balls down from the top of the screen which you need to avoid. There are a few different ways he does this , but if you stay in the middle you can always dodge to the left or the right when a ball is coming your way. He will eventually dissapear again and the whole process restarts. Once he is destroyed he will blow up and you will start phase 2 of the fight.
Boss 10 Phase 2Once phase 2 starts hit him with 2 slashes and then run to the opposite side of the stage. He will no shoot electricity high or low so be ready to jump or duck. Its always the same though so what you need to do is DUCK,JUMP,DUCK,DUCK,JUMP,JUMP,DUCK
He will then hit the ground causing fire to shoot up wherever you are standing. As soon as he hits the ground move a little forward to avoid the flames. Now use this opportunity to slash him after moving away from the flames. He will do this 3 times. After the 3rd time move to the opposite side of the screen from him again and dodge again using the following : JUMP,JUMP
He now starts to charge up before rushing from his side of the screen to where you are. He will start flashing quicker and quicker. Once he has flashed quicker 3 times be ready to jump over him. This is again your opportunity to slash him 2 times. We now start the strategy from the beginning again. After doing this 3 to 4 times he will be dead. Its time for the FINAL BOSS.
Boss 11 - The Final BossThis fight is about patience and timing. As soon as the fight starts jump and slash keeping close attention to the turret. If the turret goes up you need to walk forward,duck and face left. 2 missiles will come for you and if you need to time your slash to destroy both at the same time. The turret will now come down , when it does jump and slash to do damage,but keep a close eye on the turret. If it charges up its laser jump and slash 2 times , then once the laser dissapears it means its going to shoot , this is when you need to time your jump. When you jump do not do a small jump but push the jump button down completely so you do a full high jump. While jumping slash at the same time at the height of your jump. Keep watching the turret so you know when to slash. If the turret goes up immediately walk forward,duck and face left ready for the missiles. If the turret comes down , then time your jumps and slashes to do damage.
This Video below shows my full boss rush run.
DO NOT FORGET TO FETCH THE HEALTH PICKUP IF YOUR HEALTH GETS LOW.Semi cheat to restart Brain or Turret bossOn boss fight 3 and 8 , if you die and quickly push start , you can then choose to restart and it will start you on that boss with the same health you had when you started those boss fights.
It only works on those 2 bosses though , but use it to your advantage if you take any damage in those 2 fights.