I guess I don't really see the issue. You used your advanced knowledge of an encounter to scoop up every barrel in the act to make one big explosion to end said encounter. If someone wants to play their game that way, what's the problem? You aren't forced to use these strategies, but you can to great effect. Providing freedom like this is a great thing, it can lead to pretty awesome memorable moments or memorable fights where you use something out of the ordinary to accomplish a goal. Suggesting they have to balance the game around this is simply untrue, it's a single player game and Larian tends to encourage creative thinking like this. Toning it down seems a little stupid, because again, there is no real issue here. Ultimately DnD rewards creativity, so do Larian games, and this is a great demonstration of just that.