If you are going to attack with the sword you never really want to just run up to an enemy and swing away. They will likely just dodge or block. Its fine with your only fighting one, but if there are any other enemies they will attack you while you are busy wasting your time not doing anything to whoever your swinging at. there are several ways to ensure a more successful sword attack. The most basic being a slide. Spring towards the enemy and crouch, you can either slide into them then swing or swing before you hit them. Generally this will kill them, or at the very least knock them back. Rarely they will block this though. Another great option for opening up enemies for a sword attack is to throw something at them. Anything but a bottle or full body. I like to use severed head or other severed body parts. It stuns them long enough to kill them with the sword. Its quick and efficient. The 3rd option requires Agility 1, see that section for more info. Then there is the counter attack. best to not focus on this, and just use it defensively.
Agility 1 is by far the most useful skill in the game. Doesn't require any mana, and has so many uses. Beyond the simple climbing up places easier that most people use it for it has several excellent combat uses. If you are fighting enemies on even ground it can be used to jump above them and air assassinate them. it is not too difficult to quickly air assassinate targets by just running up and jumping and landing on them once you get the hang of it. The other major use is putting space between you and the enemy. if your cornered you should be able to jump over them. Though there are also plenty of other options available in this situation.
Devouring Swarm serves as an excellent distraction technique. Sure it can kill enemies, and get rid of bodies. but its ability to do so is rather limited. However it is an excellent tool to keep a group of enemies busy while you dispatch others in the area. Or just to open them up to sword attacks. I have used the Devouring Swarm on a group of 6 enemies and while they were all busy fighting off the swarm I was able to easily just walk up and kill them all with my sword, with very little effort.
Bend Time has near limitless potential. In general it is great for allowing you to chain together your other abilities without worrying about being attacked by enemies. or to pick up projectiles. You can collect incendiary bolts from tall boys this way.
Adrenaline Rush Is both a great ability and a really crappy one. It can get you out of a jam especially early one when you don't have many powers. a free kill or 2 is real nice, however there are also plenty of downsides. like when you attack with it you attack in slow mo same speed as the enemies and are unable to block, it is very easy to take damage while using it. Especially since if you are using it you are probably fighting off several enemies already. You also cant be in the middle of an attack animation to use it so you need to stop for a split second before you use it. I also really hate the way the screen looks to show you you have it.
ill add gadgets and misc stuff tomorrow. (im tired now, but figure you guys might still find this info useful as is)
also feel free to add your own tips and what not.