Clearly bugged. The Tips say "You can get new cards by leveling up your hero". My hero has gone from level 1 to level 7 without earning a single new card.
Good game, but at times you aren't presented with enough burgers in the time limit in order to complete the level. You end up having to fail the level and trying again to see if you get the burgers fast enough next time around.
Saving isn't a glitch. You need to allocate more space for the save cookie as the game saves a file larger than the default. Read the instructions on the save page and it works without problems.