I use the MAN(Mike) to beat the game,not the woman,so if you use the woman,this solution maybe useless.
The final boss part is in the last.
In the former level ,I highly suggest after clean a unit,wait your energy recover,when it is full again,and then go to next unit and use your gun to take advantage.I suggest you should use your guy when you face at least 4 enemy,unless you know the guys here is the last wave in this unit.And,don't cost your energy to empty,because you need energy to use guard.Yes,it is borning,because you need to wait,but it is the less risk method,and maybe the fastest method,at least for me.
Let's discuss something about ability upgrade.I recommand you upgrade the battle ability first,and then the gun ability,final, the guard ability.Because you need the
move to get advantage,and this move is the final ability in the battle tree.This move is useful because it is press simple and it is a range attack(although the range is very short),you can use it to get some free hit(which means you hit the enemy and they don't hit you)like my video show.And remember the
part you don't need to hit anyone,so you could use the move from a safe distance from enemys.
There is a issue with the guard ability and the gun ability.When you meet the final boss.You can only upgrade one of them to the highest rank.The gun ability is useful in the former level but less useful in the final boss,and the guard ability is the other way around.In my opinion,the gun still have some chance to use with the final boss like my video show,so it is not a error to max the gun rank.But I let the choice to you.
In the level 1-8,it is hard to clean the enemys to the checkpoint.So I upgrade my gun ability,although my battle ability is not highest yet.I was less patient so I didn't wait my energy to full to next unit so you maybe can do better.In this level,there is an enemy named Sharky show up,this little green shit is annoying because it has a fucking buggy melee attack.When it use its melee atack,you cannot hit it with your melee attack or you will get hit.Its attack can stuck you in the same position and attck you again and again.Yes you can maybe guard parry him.But it is risky.I don't recommand unless you have no choice to try it.The better way is keep distance from it untill it have a red spot on its bottom.That means it will range attack you in a short time,I recommand this time use
to deal with it ,when it is fall down,get to it as soon as possible to
again with it until this motherfucker to death.When you face two or three of them at once,you must find a chance to take out one of them ASAP,or you will find you get in hell.
In the level 2-4,this is a hard unit that after the BIG ROBOT VEHICLE show up,because in the hard difficult the vehicle has less health and easy to beat.So I recomand before you drive the vehicle you should try to takeout one or two wave enemys by yourself.And make the vehicle survive to the next unit to beat some enemy.In this unit ,there is a location at the top area that contain a secret star.This area also can keep the enemy away from attack you.But you can use your gun to attck them.So just stay here wait your energy,shoot,wait energy again,shoot again,etc.Use this method to save your life.(sometime the method may not working because one of the enemy may from the right side to touch you ,if this happen, go out lure enemys get away from the area and get back.TIPS,you can use
to move quickly.)
In the level 2-6 2-7 both have a fork in the road.Both choose the upside one.Because there is less powerful enemys.
At the end of 2-7 there are many waves of enemys show up.But you can stay the upstairs to wait for your energy,then down to shoot,then wait for energy,etc.Make it easier.
look my video first.Like me,you can use the
to take some free hit.And remember,
is good enough to deal with the boss because the other choice is not good to avoid the boss' counter.And don't shame about try it again and again.I tried almost 100 times.