For the four icon challenge, I chose to show commonly known things from the game Half-Life 2, which does, in fact, have an excellent story that spans across the series. 

The gas mask represents the ever-threatening Combine Overwatch and Civil Protection, the crowbar is the famous weapon Freeman often starts with (i.e. in HL2), the lambda is the symbol of the Resistance, and seeing as I couldn’t paste a public domain copy of the Greek letter into the program for some odd reason, I drew one of my own in MS Paint.  The final symbol was hard to decide on, and I spent too much of my time thinking of one, really.  Ind the end, I thought of Freeman’s glasses, and I decided to draw those myself as well.  They took the most time, being zoomed in, adding pixels, zooming out to compare to a picture I used as a reference to shape the frames, rinse, repeat.  Having zero experience with drawing or editing media of any kind,  I’m pleased with the results.

All icons used were either created by me or determined to be free to use.