I find this concept to be very interesting! I do have some suggestions though, if you plan on continuing the project after the jam. For one, I don't see the point of making the player run through the level multiple times. If they can beat it at the end, they surely can beat it earlier on, so I would suggest only having one run through. I think a remove tower button should be added. This would cause problems, because the player could delete them before running through, but you could solve this by having the player place towers before the attack, then losing control afterwards. Another thing, I wasn't sure what the game was testing of me when I ran through. It felt like it was strategic because I had to carefully place my towers beforehand, but I also could just use skill to get past anyway (and often needed to, but those times were less difficult). I think having the run through be as basic as it is doesn't allow for it to promote strategy or skill properly. Some more mechanics that encourage one of the options you intend would be a good addition. If you want strategy, then maybe decrease the player's health and include things only the player can take advantage of such as cover. If you want skill, maybe give the player a dodge or something and increase the towers' threat while still leaving it possible to get past unscathed. It's possible that some of these things were addressed later in the game though. I hope I didn't just tell you to do something you already did. Anyways, good job on the game!