I’ve played the same level a few times, so I can give you a rough idea. If the drops are truly random, you can model them as a simple discrete probability distribution—like a multinomial if there are several enemy types. Count how many times each type shows up in, say, a hundred runs, and you’ll have an empirical probability for each. From there, you can estimate the expected damage per second each type does, and weigh that against the cost of each tower. If the game introduces a “boss” that drops a power‑up after a fixed number of kills, that’s a renewal process. You can calculate the expected interval between power‑ups and time your strongest tower placements accordingly. If you can tell me the exact drop chances or even a screenshot of the drop table, I could plug in the numbers and give you a more precise strategy. Otherwise, just aim for towers that mitigate the most common threats first, then adjust as the actual drops come in. Numbers never lie, so let them guide you.