I have two words of advice to any developer when it comes advertising a video game: Vertical Slice.
Make a demo, weather it be playable or video, that has every feature you think is important to the game. Puzzle solving, combat, stealth, etc.
Also, if you do a video be sure you show the button inputs, best as ingame graphics even if it's not in the final version(people won't notice it but it'll help a lot.