This is Glory Days, an upcoming DSiWare strategy game from Odenis. If you think it looks like renowned Nintendo series Advance Wars, you're not the only one.
That's where the similarities end, however, as instead of being a turn-based strategy title Glory Days is actually an innovative tower defence game, which is played by rolling a giant cube (essentially your cursor) around the map.
You may ask yourself why bother, when the DS' stylus should let you just point at where you want to drop a tower (or in this game's case gun emplacement), but the touchscreen is taken up by a menu system for selecting which weapons you're going to use, along with a map of the large levels.
And besides, using a stylus would mean you wouldn't get to use that rolling cube thing!