As advertised, there were many, many explosions.
One small thing I noticed on the main stream of the game was that at night time (and props for getting a day/night cycle in there!) light is still being cast on all of the buildings from below the scene. This can be fixed by having a plane rotated 180 degrees on the X axis that matches the dimensions of your map. It will block the light from below and if you have other lights in the scene, they will be the only lights visible on buildings at this time of day.
I think you could probably build off of this with more mechanics as between inventory switching and the character controller, there is a game to be had here. Polishing the grenade jumping into a full mechanic would be a welcome addition, and potentially you might even want to go the route of a 3D platformer where you give the player a set number of grenades to reach a target location or blow up a distant object.