Can we use any engine or language to make these games? Like say for example, I were to use RPG Maker MV, would that be allowed?
Well, I thought RPG Maker MV wouldn't be capable of making a 2 button game (remember you can't use the mouse or a direction stick), but I don't know it well... if that's possible, you can use it!
As long as it's playable by many people (PC executable, or browser capable), it's okay.
And about language: if it's in English or French (or simple Spanish/German), I'll give you some feedback . If that's another language, the game is still welcome but I won't understand it =) Other people will :p