Dretch :
Your biggest advantages are your small size , and silent running and wallrunning. Your small size means that you are impossible to hit by most (no area of effect) weapons when actively dodging on walls by anything else than aimbots or expert clanners with a ping of 0. Even if your evolution costs nothing , it doesn't mean it's worth dying to the enemy with no chance to kill them. It is easiest to flee as a dretch , mostly because humans can hardly keep track of where you are going. Always try to attack from behind and follow them - do not jump too early because it makes noise. Sometimes you can bypass humans in the same room as you , it is easy for them to be oblivious to a dretch running past them on a wall or ceiling. It works in the ATCS long corridor - when the human comes around the corner , wallrun forward and he may not notice you. Then you can go back to him and kill him in 2 hits usually.
Dretches are better / safer killing evolutions that basilisks. But they are significantly weaker at stage 2 (helmet , pulse and flamer)
Basilisk :
That one is hazardous , because its only advantage is hard to use effectively. Basilisks are not silent when running so humans often notice you following them. Your bright pink skin doesn't make things better in dark corners , so you have to rely on passing humans not seeing you (or too late) to ambush them.
Grabbing humans on contact feels rather scary for them , so they will often focus on you if you lose your grip. Still , basilisks are excellent teamworkers , most other evolutions can take advantage of frozen humans. A basilisk can slaughter humans by himself , but not very fast , and only if grabbed from the back. If you are frontally hugging them , well they will land most of their shots. It may be worth it for a split second if you work with another basilisk who can take them from behind. It is usually a bad idea to attack groups of humans , as you need to be just as still as the human you're holding in place.
Adv basilisk is a waste of evo points for now. That green gas is countered by helmets at stage 2 , and 25 more HPs don't increase your life span too much.
Marauder :
They have said it all. Adv marauder is the funniest evolution to play as. Just be confident in your skills and learn to sense it when the humans are really trying to take you down (not merely shooting with little hope)
Dragoon :
Strongest evolution at stage 1 , and strongly overpowering rifle humans.
Your big size makes your 200 HPs worth less , except against turrets - strangely enough , those will sometimes stop shooting if you turn around them ! Dragoon is best suited to destroying turrets , more so than adv marauder even. Of course , it still requires a lot of hit & run like everything.
Playing as a dragoon requires a different perception of your health , accounting for your exposure. 100 hit points is enough to keep fighting in a base without a reactor and good weapon - but it is barely enough to escape when you are chased down a corridor by 2 lasgunners. Those are your worst enemies at stage 1 - they are quiet , unavoidable , and usually relentless , especially when you whine in pain. Do not be fooled by their slow damage - they can easily kill you if you don't retreat soon enough (around 120 hps when one is around)
Learn to pounce well. Your flight should be a low arc ending on a human's head preferably. It works best on predictable players with a low ping. Campers are very vulnerable to you when you have a clear shot - leap over turrets to frag and leap back out of the base. Pounce is rather random in normal close quarter fights , try to corner humans and don't lose sight of them.
Each human weapon requires different tactics to counter. Painsaws are rather threatening and can kill you fast - you need to carefully stay out of their range when striking , and just disengage when low on health. Avoid cramped areas when a bold blade runner is going for you.
Shotguns mean that you should leave around 90 hps , and time your dodges according to their rate of fire.
Mass drivers aren't really dangerous to you , try to leap past them and strike to waste their shots. Again , disengage when not in good shape.
Chainguns are usually too dangerous to you , but you can strike them by surprise from behind. When sprayers are around , your hit & run reserve is a good bit lesser.
Pulse rifles are a big threat at stage 2. Focus on dodging them and stop attacking as soon as you feel they are chasing you - if your HPs are still high , leap back at them around a corner like you would for a rifle human , it may work just as well. Just don't stay around them for any length of time.
Flamers are just as hard to fight , but much less threatening as soon as they leave their teammates. Pounce them when you have a clear shot from behind.
Lucifers are your bane , one shot kill. Don't bother playing as a normal dragoon when they are around. Or at least don't engage them in melee range.
Adv dragoon is a completely different story. Even if it may feel limited , your ranged attack is your best ability by far. The projectile arc is hard to master , but this attack is deadly. Only use it against stationary targets , such as structures and campers (especially jetpacks)
Don't be afraid to be cowardly and run away a bit when you have 200 hps and used your 3 shots. More often than not , it is time for tyrants or other adv dragoons to do their share of the base wrecking job.
Interestingly , your hull is bigger , so you may not pounce in places where you could as a dragoon. But you may reach higher grounds thanks to the extended pounce. Also , your 50 extra HPs give you a second chance against lucifers.
Tyrant :
What is there to be said about that one ? Charge and smash. This evolution has no real finesse and is basically a dragoon specialized in base destruction. It is also more suited at fighting battlesuits , killing them in 3 hits - but it still takes some skill.
Just don't forget to run away at half health like other evolutions do. You are large and cannot jump high , so watch out where you are going to not be stuck. Call for the assitance of a dretch or advanced granger if you cannot leave a room - they can boost you out of it by wallrunning under you. It is an important trick - a tyrant can rule the Tremor underground and defend the base here very well , but will need someone to get out and attack the human base.