Yes, the Seattle Seahawks will get into the playoffs. The NFL preseason is no indicator for how good or bad a team will be. Preseason games are for players to get into game shape and for rookies and free agents to display their skills and try to make a team. Teams have went undefeated in the preseason and had terrible seasons and lost every preseason game and had great seasons. Preseason games don't mean anything in the big picture.
The Seattle Seahawks will make the playoffs again this year as they are led by star quarterback Russell Wilson and a stellar defense. The preseason is the time to test out the players that will be the backups and the intent is not to win but to see what you have in those players.
The Seattle Seahawks do not appear to be a playoff contender this year. The team has lost two preseason games that they should have won. Furthermore, there are other teams that are playing more competitively this season; which means that Seattle has a lot more competition to get into the playoffs. In short, because of Seattle's poor preseason performance and stronger competition from other teams, the Seahawks will not likely make the playoffs this year.
No, the Seahawks may not make it to the playoffs this year if they keep on going the way that they are going. The Seahawks were the champions of the 2013 season but since then they have not been able to put together a repeat performance. With many of the same players, most people would expect them to make it to the playoffs, but they need improvement.