This is an old game that predates the current GT submission system. I am reuploading it so that all my GT games will show up on this page: https://www.glorioustrainwrecks.com/games/*/sylvie
Cactus Block is a "gambling platformer". Use WASD to move, and click to place either a cactus or a block. You don't know which one it will be. Press R to restart the level if you get stuck or fall off the bottom.
In 2013, I made a remake of this game with added features called Cactus Block 2013. You can download that here: http://love-game.net/cactus.zip