One of the most basic tools and an amazing starting place for many people is Game Maker. If you download a copy of this and follow the tutorials you’ll be making games in minutes not hours. It has a simple drag and drop approach to building the pieces of your game and the logic that powers it. If you have any doubts about it restricting what you want to make check out Spelunky to see what it can do once you’ve got a bit of experience.
Though the developers themselves admit they let the tool stagnate for some years there have been recent efforts to get t up to modern standards. The free tool will export to PC and Mac but adding iOS, Android and HTML5 support can get quite expensive.