Pretty fun concept, although I think it could be more fun if you started the game by either aiming your gun or having the assassin aim their gun, then fire you out, so you start with a lot of momentum. You could make it so you lose momentum over time and start to fall, so it could sort of be a puzzle kind of game where you have to make strategic choices about which targets to aim for. There's a lot of ways an idea like this could be iterated on!