Undertale Research 

When I was playing through Undertale I decided to do a pacifist run, meaning I couldn't hurt a "monster" in the entire game. The point of such a playthrough is to cause the player to learn about and develop feelings for the "bosses" in the game, who turn into their friend rather than always being the conventional foe.

The final boss is an old friend (sorry I'm trying not to ruin the game) who tries everything in his power to defeat you, but in this run, no matter what, you stay determined and continue to try and help him. He keeps attacking you and there's nothing you can do about it, getting to a point your health goes into fractions of 1 (another interesting and unique aspect of a game)

This makes the player feel helpless and in that moment I realised that games can make the player feel emotions through gameplay. Many games in the past have done this before. For example, in mega man x (I know I keep bringing it up) at the beginning of the game you fight sigma, no matter how good the player is, he will defeat you and make you feel hopeless. This gives the player, not the protaganist, real emotion of defeat making them really want to defect sigma. (in other words, "its personal now").

Also playing through Undertale (a game made in game maker) has really made me think how the creators put the game together. I found myself actually just stopping and looking at the sprites or the surrounding area.