This is a really fun game! Simple idea that gets progressively harder if you're not acting quickly enough. The concept alone makes it an enjoyable game, and I'd say the game's writing is its strongest suit.
The game's weaker points would be that .exe files are represented look like video format files, and can be a hurdle to get over at first, and there have been cases where that thumbnail is put on .png files. Bigger issue was that the 240$ level seems unbeatable, and it would have been nice to have a clear end you worked towards, such as trying out the hip new PhysOS for a week or something. Feeding either Cactus or self doesn't seem to do make any difference, but it's still a fun gag.
A way to increase difficulty would be to let players be able to send the wrong files, but I'm a bit glad you can't. It's not hard to imagine that being a cut feature for the sake of balancing, and the game doesn't need that level of depth.
Very enjoyable! Top ten games I played all year.