A "level pack" typically refers to additional content or additions to a video game or toy, usually consisting of new or extra levels or challenges for players to explore and enjoy. Full definition
The original Alien Breed is included, plus the special edition that was released the following year, and three new level packs with four levels each brings the total up to thirty. (thevitalounge.net)
We are working hard and will release new level packs in free updates very soon. (andyemulator.com)
It's worth bearing in mind, though, that three of the arcade hubs are found in other level packs, which are sold separately. (tiredoldhack.com)