Let's Play X-COM Enforcer Mission 4
More civilian rescuing, and the first boss enemy of the game. It's a Reaper, ostensibly, and more specifically Professor Utonium calls it a 'giant' Reaper. That's not meaningless: we'll be fighting regular Reapers soon, and they are way smaller and also don't try to vomit all over you. It's an odd way of introducing an enemy type.
There's not a ton of strategy to the fight. Keep away from the Reaper, don't let it corner you, and keep shooting it.
I also finally get a maximum Hot Streak, so let's talk about that mechanic: killing enemies builds your Hot Streak. (Or maybe hurting them at all? It's difficult to keep track of the distinction in all the chaos) Taking damage massively lowers your Hot Streak. The first thing the Hot Streak does is provide bonus Data Points at the end of the mission based on stuff like what your highest Hot Streak was. The second thing it does is upgrade all your weapons (Except the laser) for a period of time (It doesn't end instantly when you drop below such a level, but it doesn't last the entire mission if you do drop below such a level: I'm not sure what the details are), specifically to a level matching the demarcations; so a Level 2 Hot Streak raises any weapon that's Level 1 to Level 2, but has no effect on weapons that are Level 2 or higher. The third and final thing is that hitting a maximum Hot Streak showers you in powerups for, as far as I'm aware, as long as you manage to maintain maximum Hot Streak. This even includes powerups you haven't unlocked, such as the hover-drone gun buddy you see in this video.
Basically, the game rewards you for playing well.
This mission's Bonus game is, uuuh, a thing. Bust crates to unleash Data Points, then try to collect them. Ideally you should be firing at all times, and also ideally you should be firing the Blade Launcher in particular at all times to maximize collection. If you can't, at least prioritize the big pickups. I think it's a pretty boring Bonus game, but it's one of the better ones for potential Data Point gains so from a winning-the-game-best sort of standpoint it's a good Bonus game to get.
See you next mission/