Here's an updated version of my Excel Tower Defense game as mentioned in the recent Excel AMA on Reddit.
Shortly before Office 2010 shipped, the Excel test team was instructed to take a couple days to make solutions that could stress test some of the new features. Because I enjoy playing tower defense style games I decided to make one in Excel using a mixture of many of the new features in that release (Slicers, cross-sheet dependent Conditional Formatting, the AGGREGATE function, and Sparklines). As an added challenge given my familiarity with calc in Excel, I wanted to see how much of the game could be written without using any macros.
I spent roughly 4 work days making the first playable version, including significant time spent discovering, reporting, and working around a number of product bugs along the way so that I could complete the game and also get the product bugs fixed before shipping. After the initial version was up and running, I gave it another 8-16 hours of hobby time adding features and fixing bugs in my solution, such as adding localizability and making mouse UI more robust. In the years since then, I’ve probably only looked at it for an hour or so per year, fixing small issues and adding support for sheet zoom levels and non 96dpi Monitors.
While you may notice that the file contains macros, these are only used to enable mouse UI (hover and click). To play the game without enabling macros, simply Unhide the “Game” sheet and then after switching to it, use the keyboard to select cells. Pressing F9 to recalculate will trigger the next frame, treating the active cell as a mouse click. For best results, please make sure to close any other books before opening this one and don’t open any other books at the same time.