The Drillmaster is similar to the Chaos. The Drillmaster loses shield HP when hit but increases max shield anytime he uses a skill. However the Chaos loses Health but can only increase max by killing an enemy. So since the Drillmaster just needs a skill. Then the best skill to use is the Grenade. All you have to do is equip the Drillmaster and make sure it is upgraded enough to increase max shield. Then equip Grenade and max out Grenade cool down talent. Then as your playing a room, throw the Grenade even if you don't hit anyone. It will increase your shield after every skill use. And grenades cool down the fastest. So after enough skills used you can avoid being one or two shotted by snipers. But only one from an engi.
Jumping up walls
Before you go jumping on walls you might want to get a sniper I would recon the black mamba. The best map to do this on is the rocky chasm the best area to do this is where the boulder is stuck between the two walls go to either side of the boulder just start jumping at the wall and you will eventually get all the way up the wall if you want you can jump on the boulder.
No way out of room
There's one map, the indoor map. You put a shield inbetween the two walls and if they jump on top there stuck and the only way out is to break it so there stuck in there for a short time and you can get some free kills.
Snowman and armour
If you have the snowman armour fully upgraded, you can become invincible for a while. When invincible you cannot move or shoot, but use it to let your shield recharge, your skills recharge, let energy weapons recharge and you can charge up the Imp Handannon if you have that too.
Various Gameplay Tips
Head shots worth more money
The more you kill, the more experience you gain
Each weapon has its own capacity and personality e.g. Marauderiii can shoot short to long range and reduce speed for 10% while Heavy machine gun shoot longer but reduce speed for 25% etc.
Each battlefield has its favorable position, for dessert, you can jump up to top of the cliff behind red army spawning place, where a bridge like position. You can use the marauderiii to shoot everywhere of the dessert. But if you find enemy there, go under the "bridge" and shoot his name with stinger launcher, he will blow up!
For beginners, 1vs1 is the best way to gain experience
Don't be afraid of high level players if they kill you as you can gain 200 experience points and 100 cash even you lost
Planting turrets can distinguish invisible players, shoot where it shoot ! This is the best way to kill invisible players in short range
When you have points for talent ( gain from finishing targets e.g. Get 100 kills etc. ), be sure to upgrade shield HP first !