q2dm1 is one of the most interesting teamplay maps, as it's enough arcade and strategic. The best is to play from points, and for this purpose you're to find out the level priorities at once. The perfect situation looks like this. One player is in a room , preferably with the Chaingun - he is to protect the yellow armor and the Megahealth, and also cover the territory by the water.
The second player must stand on the elevator, better with Rocket and cover the rest, also watching respawns by the Chaingun and by the upper Rocket.
Other two players must interact precisely and make as many frags as possible. For that you must get two Railguns and then simply control respawns on the level. If you control a room, and took a Railgun from a killed enemy, ask your teammates to replace you, and then try to make quick frags on respawns. The perfect position is when ona railer holds the arena, and the pther - the territory by the water.
If it's an arcade game, the arena railer must show himself a bit from the room and start aiming at the further respawn location - there's always someone showing up. But you have to remember about the possibility of enemy's respawn at the Shotgun and try not to miss it. usually the player on this position makes a lot of frags, and its important to place there a very good sniper.
The forth player conrols the water territory. The best is to stand on the border above two packs of rockets and control the respawn by the water. Also don't forget about the possibility of an enemy appearing at the upper Rocket. When Railgun ammo is over, ask your teammate to cover you, and swim to the Railgun.
If your team manages to take such control over the level, consider you've got a serious frags priority. But more often the game on q2dm1 turns into terrible mess, and you can't manage to hold all the four points. The best then is to control the room and the territory by the water.
After that you can try to take the elevator - the best way to do it is from the arena with a Railgun, as the enemy may simply stand above the elevetor and look down.
If your team lost all positions and starts giving away frags, better act like this: two try to get the Shotgun and the Rocket, two others sit in the water by the Railgun and wait. It's important to perpare the attack correctly, and only then you can really change the situation on the level. Next step: one tries to enter the room with the Megahealth fromthe arena, second - from the water edge, and the rest try to come from the water with Railgins. A big skirmish is almost imminent, but railers have more chances, as the Railgun is the most effective weapon on q2dm1.
Another important moment in the game: you need the railer controlling the arena, to spot in time when the adversary team starts playing defensive and stops showing on open places, and let the team know about it. At this moment the player controlling the room must go to the water for rockets and briong them to the teammate with Rocket on the elevator. At the same time the railer at the water must swim for the Railgun and bring ammo to the railer on the arena. As a result of such manoeuvers you'll have great level control reinforcement.