I find that most sport games are designed for gamers (as opposed to casual gamers such as myself). They have many control options and the learning curve is often quite steep. The focus is also often placed on a career mode, which requires several hours/days of gameplay to appreciate.
NHL Slapshot caught my attention after I have read an article that mentioned that the game was designed for a younger audience (and also because I am a huge hockey fan). The controls are indeed much simpler than most hockey games I have played. Most commands can be made simply by waving the hockey stick (passing the puck would be an exception). I can also play with my 8-year old daughter on "pro" difficulty setting without any of us being overwhelmed by the other team. We like playing at the peewee or bantam level, since the team is composed of only 3 players and it is easier for us to control the gameplay.
NHL Slapshot does provide a career mode, which I have not explored much to this date mostly because it does not appear to support multiplayer gameplay.
All this to say that NHL Slapshot is a simpler arcade style hockey game, which makes it a perfect family or party game. Avid gamers looking for a hockey simulation game may be disappointed however.