[twillight]

Strike Force Heroes 2:
Engineer Killstreak Bots:
#1: Disappears if hero dies. Disappears after duration expires. Disappears if shot down. Has low damage. Shoots in straight line. Pretty bad bot.
#2: Follows you around. No idea if it does anything.
#3: Deals damage in a fixed radius. Has considerable HP, and 18 sec duration is pretty long. Deals good damage (against very easy oppoents). Can give you considerable amount of kills if you put it at an enemy spawn-point and you keep killing the enemy at other places. If the enemy wears katana though, they can kill it in no time, but wth.
#4: 6 killstreak is still too much, and it can't even be 5, as engineer don't survive without nanobot healing. Places a turret with homing missiles. Unfortunately the aim does not notice walls, and thus shoots missiles for no use. MIGHT have good damage, but I'm not sure.

Hard chalklenges:
#1: play semi-defensive: stay in the bottom, only going up if you rly run low on life. Do not let people behind you, and shoot anything what moves.
#2: play defensively: put your turret at your team's bag, stay at the bag yourself for top priority. Your team will sooner or later DO capture bags, your job is to prevent enemy capturing yours. Enemy at your half of the field mean less enemy protecting their half, so killing the enemy is NOT priority.
#3: Juggernaut is perfect here, as it has a "no burning" skill, "less splash damage" armor, and good health. Just don't forget to shoot like no tomorrow.
#4: Bring Juggernaut. Bring armor what gives extra melee damage. Don't know if it works, but try the attachment you think would give best boost from what you have. Play coward: at the middle of the top platforms is a "barell" - crouch there until you get full HP and an enemy stands on the top of the "barell". Then jump up, and hit it hard. It'll jump on the farther side of the map (the AI just lub the transporter beam), so run after it and finish it if noone follows. Go back to your position after. Crouch to show smaller target. With luck the AI will even get weapons what can make it commit "suicide": self destructing damage. That can happen by the plasma-beam at the bottom (unlikely), flamethrowers, acid sprayers, or rocket launchers (any version).
#5: Play DEFENSIVELY. Bring weapons to do ONE HIT KILLS, as on this level all the AI does that. Unfortunately your team WON'T mae the job for you. So the strategy for this is to run for the baggage, shoot down/harm anything you pass by, and make every bullet you use count! Then this is all about persistance, as some very precise conditions have to meet: 1) get past the enemy soldier till the bag. This is suggested to be done on the upmost platforms as that is the fastest. Die if you see your team not capable holding the enemy, and use the middle platforms if you see the enemy making a combined ambush. 2) Be able to grab the bag. This means the enemy team is not dieing in that moment, respawning on your head. 3) get back to your base. This requires the enemy focusing on the arriving remains of your own team. If there are none, you won't reach back. To reach back it is suggested to use the bottom platforms, as that gives the most cover, and makes following you a little harder. The nastiest thing here is, that everyone shoots through walls like they're not there. Killstreaks are disables, but you wouldn't be able to use them anyway.
#6: just camp at one of the bottom corners to be safe.
#7: I am not sure for this. It is obvious that more HP and more protection from burning and splash damage helps. This means either the merc, or the juggernaut. The weapon-resolution is either random, or works like the "kill to downgrade your weapon" challenge. If the first, then it is RL chance, if it is the later, you have hope. Tips that will help: 1) avoid blowing up yourself. 2) Never aim downward with the flamethrower, as then you'll burn yourself, commiting suicide, loosing points, probably going backwards on the weapon ladder. 3) Flamethrower is what sux most. You have to get rid of it. Go for a garbage-kill, meaning finding an opponent who just survived a fight with minimal HP, and try to kill THAT. Otherwise this challenge is insanity with all the nifty effects, ka-booms and all.