Thank you very much!
I'm not sure if you were using WASD or the mouse in this case - in either case, it is true that the blue dots can't be clicked (only the tiles can be clicked on, and, well - since the dots don't block it, that could result in misclicks), and it's very understandable that that's misleading and something that I need to fix haha. Thank you for pointing it out!
As for keeping the rounds beatable, this was mainly via playtests and tweaking plenty of variables, and a bit of coincidence, too. The target score grows exponentially to make it more and more challenging, but I do think that thanks to the way the levels are generated and how scoring works, it's theoretically always beatable.
The way levels generate is decently simple - a value representing the number of tiles is given, and the code will then repeatedly select a random tile and place a tile next to it at a random available direction. Every level the amount of tiles is increased by... I think 2, not 100% sure, but in any case, it keeps on expanding over time. Depending on how many tiles there are, it'll spawn in an amount of buttons, to increase the amount of distance the player needs to traverse to beat a level. Main takeaway, levels are randomly generated, but the amount of tiles a level will have isn't.
...in any case, since the level keeps expanding, and since the score per enemy placed also increases, I think it's technically possible to keep going forever. Also, you get more levels per round beat as you beat more rounds, so that also helps. It does mean that levels will also become more and more challenging due to the large amount of enemies required.
...bit of a ramble, but I hope that helps explain the design behind the scoring, haha