Jetpack is an old game, that has become freeware (abandonware) a few years ago. This game is fun and challenging. The goal in jetpack is to collect all the green gems in the level to open the exit door. Along the way are evil robots that want to kill you.
Levels are built to make the player think. In the levels are different types of terrain, some are destructable with your phaser, others are not. Also levels contain things like ladders, and teleporters and barriers which need to be deactivated with switches. Monsters can use teleporters and switches.
The main way the player moves around is with the jetpack. Some levels though make you get your jetpack before you can fly. You have a set amount of fuel so don't waste it all.
The enemies in jetpack all have there abilities. Trackbots can move around and go up ladders and in teleporters. Springs only go up and down. Missels go in a set pattern. Spikes only move diagnolly, ect. These mosters can't be killed. The game has nice graphics but the enemies/player look pixelish. Sound in the game is ok, with many "death sounds" too.
One of the cool features in Jetpack is the editor. You can create your own levels and play them as much as you want. The editor is easy to use and levels can be made quicly. Another feature is the "Boss" key. This would pause the game and put you in a fake MS-DOS command prompt so your boss wouldn't see you are playin games (More games should have this lol). Kinda useless now but still a cool feature.
This is a fun puzzle game worth to check out.