From my experience playing recently, if one side doesn't end the game within ~15 minutes, the game ends up going on for 50+ minutes.
The majority of this time is spent in a sort of "stalemate" scenario. These games are extremely frustrating because they end up being either games where fights or objective control ends up in even trades constantly, or one team is able to turtle insanely well. I've seen the turtle happen from both sides, but it's easier for marines since ARCs can take care of alien structures through walls.
Essentially, this seems to happen because once players buy/evolve, they are at their strongest. However, if you die, you lose resources that you spent, and your player is essentially "reset" to an initial power state. If both teams blow all of their resources for a "game ending" push, and they both end up wiping each other out and going even, it essentially evens the game to an equal power state (much like the start of the game.) So once this happens, both teams lose a bunch of pushing power, and you sort of end up playing the game as if it just started.
In one game I was on aliens, and we controlled 90% of the map. Almost every single resource node. This was 50 minutes into the game. For the next 20 minutes we were trying to wipe them out as they were turtling with what they had, and spending any resources on turtling. Resources came in extremely slowly, so we weren't able to evolve for an extremely long time, even with nearly every resource node on the map. We ended up winning at the 80 minute mark, but marines hadn't really done anything for the previous 30 minutes. It simply should not take that long to close out a game.
I believe the game needs to have a push for games to end sooner, to prevent this. Hour-long games are great if they're action-packed, but they're boring if one team is obviously winning but cannot end it. There should be a greater reward for controlling the map after a certain point in time. Resource nodes should give MORE resources over time. For example, after 30 minutes, a resource node should start giving more resources than normal. In a scenario where both teams are even, they will be able to buy/evolve MORE often, allowing MORE pushing power, and encourage MORE fighting. If one team controls more of the resource nodes, it will favor them much more. In the scenario I described above, we would have been able to end the game quicker, because we would have been able to afford fades/onos for the pushing power. Skulks are extremely useless at this point in the game (vs grenade/flame thrower spam into hallways), but without resources, you will spend all of your time in this form. You should not be forced to do this with 90% of the map in your control.
I compare this sort of thing to a game I play quite frequently, League of Legends. Games are on average 30-40 minutes. However, the game attempts to push games to end over-time, meaning at the 60 minute mark, if one team kills the other team, it's practically over. Games CAN last longer than an hour, but because of the way the game is set up, it becomes exceedingly difficult for one to simply drag the game out, unless both teams simply refuse to fight. A few ways it does this is increasing respawn timers, increasing gold income, and increasing the strength of the AI minion. This is much more fun/rewarding, as the tension will build as the game goes further into late-game. Both teams sort of "level out" in terms of power, and it comes down to controlling objectives and team-fighting. Whichever team makes a mistake will generally end up losing at this point in the game.
As a long-time NS1 fan, I've enjoyed my share of 2 hour games.. but they were extremely rare. In NS2, this is pretty much the regular game you'll be in, on a public server. There will be long periods of no-action and this is not fun for either side.
The majority of this time is spent in a sort of "stalemate" scenario. These games are extremely frustrating because they end up being either games where fights or objective control ends up in even trades constantly, or one team is able to turtle insanely well. I've seen the turtle happen from both sides, but it's easier for marines since ARCs can take care of alien structures through walls.
Essentially, this seems to happen because once players buy/evolve, they are at their strongest. However, if you die, you lose resources that you spent, and your player is essentially "reset" to an initial power state. If both teams blow all of their resources for a "game ending" push, and they both end up wiping each other out and going even, it essentially evens the game to an equal power state (much like the start of the game.) So once this happens, both teams lose a bunch of pushing power, and you sort of end up playing the game as if it just started.
In one game I was on aliens, and we controlled 90% of the map. Almost every single resource node. This was 50 minutes into the game. For the next 20 minutes we were trying to wipe them out as they were turtling with what they had, and spending any resources on turtling. Resources came in extremely slowly, so we weren't able to evolve for an extremely long time, even with nearly every resource node on the map. We ended up winning at the 80 minute mark, but marines hadn't really done anything for the previous 30 minutes. It simply should not take that long to close out a game.
I believe the game needs to have a push for games to end sooner, to prevent this. Hour-long games are great if they're action-packed, but they're boring if one team is obviously winning but cannot end it. There should be a greater reward for controlling the map after a certain point in time. Resource nodes should give MORE resources over time. For example, after 30 minutes, a resource node should start giving more resources than normal. In a scenario where both teams are even, they will be able to buy/evolve MORE often, allowing MORE pushing power, and encourage MORE fighting. If one team controls more of the resource nodes, it will favor them much more. In the scenario I described above, we would have been able to end the game quicker, because we would have been able to afford fades/onos for the pushing power. Skulks are extremely useless at this point in the game (vs grenade/flame thrower spam into hallways), but without resources, you will spend all of your time in this form. You should not be forced to do this with 90% of the map in your control.
I compare this sort of thing to a game I play quite frequently, League of Legends. Games are on average 30-40 minutes. However, the game attempts to push games to end over-time, meaning at the 60 minute mark, if one team kills the other team, it's practically over. Games CAN last longer than an hour, but because of the way the game is set up, it becomes exceedingly difficult for one to simply drag the game out, unless both teams simply refuse to fight. A few ways it does this is increasing respawn timers, increasing gold income, and increasing the strength of the AI minion. This is much more fun/rewarding, as the tension will build as the game goes further into late-game. Both teams sort of "level out" in terms of power, and it comes down to controlling objectives and team-fighting. Whichever team makes a mistake will generally end up losing at this point in the game.
As a long-time NS1 fan, I've enjoyed my share of 2 hour games.. but they were extremely rare. In NS2, this is pretty much the regular game you'll be in, on a public server. There will be long periods of no-action and this is not fun for either side.