Just heighten the level of security of the game. I just hate the thought of dumb ass people taking away things we enjoy through violence. To me it seems they win.
This train of thought just makes no sense to me. There are bigger things in life than us, the things we enjoy, and winning and losing. Two people (so far) DIED today. Whoever was behind the bombings already "won" the instant the first bomb went off.
After the bombs detonated, the NHL (and the police, etc.) simply had to make the most reasonable decision. You can't just make an irrational decision just to get "revenge" against the bombers by continuing to play the game. It's not like they give a damn anyways; the bombing wasn't about hockey.
The arena is not very far away from where the bombings took place. They didn't (and might still don't) know if there are any undetonated bombs left. They were trying to get people OUT of downtown Boston. Would it even make sense to try to get the players into the arena to play the game? There could've been a bomb under the ice rink for all we know.
Heighten the security? What exactly does that consist of? Hiring more security guards? Because they better know how to detect potential bombs and know how to defuse them. As others have said, the police had their hands full. Not likely they could find anybody on such short notice, let alone during circumstances such as these.
Letting the game continue as scheduled would either encourage people to go to downtown Boston to watch the game, which would be incredibly stupid given that there could still be undetonated bombs around, or would result in nobody showing up to the game at all (since most people don't want to walk into a bomb zone). Would it make financial sense to play a game with zero attendance? Would anybody even be in the mood to watch the game at home given the circumstances? Would the players play at anything close to 100%, or for that matter would they even agree to play?
Finally, the US government/Boston police may not have allowed the game to proceed even if the NHL wanted to given the obvious safety concerns.
In the end, cancelling the game was the only alternative.