A lot of people brought up Undertale during Rad Squirrel. Undertale is the obvious choice for Grace to play, but not for me to make comics about Grace playing. There would be absolutely no conflict for Grace, and it would just be her playing the game properly without killing anything. The whole thing would mostly just be spoilers for a game best played unspoiled.
A more interesting scenario would be Grace playing a kill everything run of Undertale, but a) that would be extremely out of character, and b) would still be a ton of spoilers for a game best left unspoiled.
Deus Ex: Human Revoluion, on the other hand, is full of things for me to poke fun at. I promise there'll only be one observation about the absurdity of the glasses, and it's one I haven't seen mentioned before, so yay.
I've been told about a game called Ninja Pizza Girl (Trailer) by a LOT of people after the last comic, which is only natural. It has a parkouring ninja delivering pizza. There's connective tissue there.
Some people, however, have been saying "this is the game you want" or "you mean this game", and that's where things get a bit frustrating for me.
The game I want has open world parkour with a very basic plot and simple goals. Delivering pizza is secondary to the mechanics. A linear sidescroller is not at all what I was talking about, regardless of pizza and ninjas.
(Which doesn't make that game bad. It's just not what I was talking about)
Basically, I want the parkour from Assassin's Creed or Mirror's Edge (though leaning more towards the former) with an open world and more arcade style gameplay. Pizza delivery is but one of many simple goals that would work, and it's the mechanics that matter.
Really, if one wants to compare my idea to an existing game (other than the ones with parkour already in them), Crazy Taxi is the closest comparision I can think of. The gameplay's significantly different, but the "get something to this place the fastest way you can thnk of" aspect is certainly similar.