Regarding number 3, that's because plasma weapons in-game don't work the same way they do on the tabletop or in the lore. When they overheat in EC, they just need to be vented to cool down. They don't explode in the user's hands and shower their user with burning-hot plasma that melts through the armor and flesh in seconds.
81) The ability to circle strafe manually was lost to the Dark Age of Technology yet is essential for Melee in particular: a technique that no race of the 41st millennium has been able to re-assimilate. Melee lock will home in on where your target was 3 seconds ago as you watch your mis-guided attack trajectory slingshot off into the distance and your enemy will already be behind you. Actually your already dead due to lag. 82) Melee angle trajectory alteration: More techniques lost to the Dark Age of Technology that affects Melee only: If a Ranged class is standing on a ledge above or below you (1 millimeter in either direction is enough), he can and will aim at any angle and shoot you while you flail your Melee weapon about impotently in a fixed 90 degree angle straight in front of you.
83) Just when you think you're doing well. Lias Issodon will show up to prove you're not. He'll just kill you 40 times in a row with his Stalker Bolter. And there's nothing you can do about it. 84) Distance will not save you from Lias Issodon 85) Cover will not save you from Lias Issodon 86) Killing yourself is not a valid method for escaping Lias Issodon. He'll just ask the nearest psyker to send him to hell, so he can continue killing you 40 times in a row with his Stalker Bolter.
*kicks open dah door* I got dem rule fings!!! Wots dat numba......oh roight! 87: Orks are sneaky... we hoide among day Spoiky and Beaky Marines 88: Blue for Orks is Lucky...Blue for Marines....means yah are a git! 89: Go around dem corners slowly.... sometimez a an ally moight have der Powa Fist pulled back and pounch yah in dah teef
90) Don't play chicken in a vehicle with a power fist user whom is reared back for a charged attack, you're going to lose! At least it's hilarious for the rest of us when you do.
91) Krak grenades are not for their intended role as anti-vehicle. They are to be planted on the face of the closest marine before running away from that person's now inevitable doom.
92) be sure to anchor a rhino or pred to the ground when not in use, they have a tendancy to fly away.