This level requires a lot of grenade throws to reliably take care of enemies. While the very beginning of the level was solid, later on I am waiting some time for the grenades to actually explode. This adds up quite a bit which is where some timesave can come from. Before entering the secret room, it is actually possible to take out all three enemies with a single grenade but it relies on a bit of RNG that the first enemy doesn't just charge you but you can still spawn the third one in. Sniping the pilot can be done faster as well.
It's very clear that the primary challenge that the developers of Agent Under Fire wanted the player to partake in was obtaining high scores. You need high scores to unlock single and multiplayer rewards and your highest scores are saved and displayed under each mission. Naturally, the beginnings of