Alien Breed 2: Assault

I recommend going for this trophy on the level 'Vanguard. You should hit the 8 minute mark during wave 5. The trophy will not unlock at the score screen. It unlocks once you press try again or go back to the main menu.

-'Vanguard' is a rectangular room with vents that expel harmful gases.
-All the items situated in the room re spawn at a surprisingly fast rate.
-The center of the room has 3 Large Health Packs that spawn on top of the gas vents. There is also a Hyper Blaster near the center vent, close to the opposing wall that you enter from. There are 2 Small Health Packs that re spawn at either side of the map and 4 Pulse Rifles around each corner of the room.
-Don't bother using the Pistol.
-For at least the first 3 rounds you will want to make a route passing all of these pick ups. Ignore everything else, except for maybe stun grenades.
-Use the Pulse Rifle until around Wave 4. During this time save up as much Hyper Blaster ammo and Health Packs as you can.
-During Wave 4 you will want to switch to your Hyper Blaster and run to one of the corners. Here you will only be exposed on 2 sides. You should be able to hold off the majority of the alien horde this way.
-When you feel confident that the aliens numbers have dwindled then you should run out and grab as many Health Packs as you can find and restock up on Hyper Blaster ammo and any Pulse Rifles on your way. Be quick about it because after the 5 minute mark the aliens can overwhelm you rather quickly.
-If you are having trouble then maybe you should pick up the Stun grenades as well. You can use these as a last resort if your being overwhelmed. Be warned though, the aliens can do a lot of damage in a short amount of time and they may kill you before you get your Stun Grenade out. You can also get killed if you fumble when changing your items from the Stun Grenades to a Health Item.
Good Luck

Please Note: It has been reported to me that the game sometimes glitches around Wave 3 if you stand in one of the corners. For some reason the aliens don't attack you. I have not been able to duplicate this though.