It's not everyday that you get to see a game designer mature through his games, but the Trapped series provides a window into the Flash experiences of its creator Matt Ruggia (AKA lost50). This series of 5 adventure puzzle, maze games starts with a minute long "training level" and progresses to 30 minute long (if you play it ten times and memorize the maze) high quality casual gameplay experiences.
You are a lonely little arrow, trapped, as the title suggests, in a maze full of simply-shaped enemies set on keeping you there for eternity. Using the arrow keys for navigation, you must battle and puzzle your way through many rooms, sometimes with the aid of a map and your trusty, upgradeable weapon: the bomb.
Various installments feature everything from boss battles to fellow trapped arrows. The games feature a wonderful host of bad guys, each with its own attack pattern, abilities, and health. Often an unlocked door will pit you against an ambush full of various enemies. Strategy comes into play as you must keep in mind your own health level to get a good score at the end. Also nice is that you can choose between five music tracks instead of listening to the same loop over and over.
Although the fourth and fifth installments are really the most developed in graphics and in gameplay, it is worth playing the first three to get the full experience.
The entire collection can be found here.