N-Game v1.x (not v2, it has worse level design)
(click image for site)
( A tad violent with the death animations, but it is a minuscule stick figure on the screen, so it isn't so bad. )
This is one of my favorite skill based Flash Games. It has very precise and satisfying controls where the length of time you hold down a button influences your movement.
There are a wide variety of well designed levels with different types of enemies that are focused on preventing you from reaching the exit door on each level.
The enemy types include:
Drones that move around the map with varieties that shock you if you get too close (with another sub-variety that will rush in your direction if you come into its vertical or horizontal line of sight), shoot a laser blast in your direction that lasts for a few seconds, or shoots a machine gun type weapon at you
Stationary enemies that have a target locking laser that tracks your movements until it gets a good shot, or another type that shoots a seeking missile that you need to try and evade until it crashes into a wall
Drones that move along flat surfaces to shock you when you set foot on the surface
And mines that make precision jumping necessary
As a timer runs down, you need to run around the level, jumping off walls, through one-way gates, off of jiggly blocks, or on jump boosters to collect the exit door key that could be locked behind additional gates with keys scattered about the map. Collecting gold helps increase the time, but it is often a trap to go for the gold.
It is a very challenging game that can be frustrating at times, but the satisfaction of completing a tough level is worth it.
Sometimes getting close to the end of a level can make you overly cautious and lead to disaster like this:
Expand to play GIF