@lynnesbian the following statements are all true facts in this universe: Alien Swarm: Reactive Drop's developer tools crash at startup unless you've changed your screen resolution in the game at least once.

The person who compiled the part of the code that is broken left Valve in 2017 and the code was lost in a server move in 2018.

Both Alien Swarm and Alien Swarm: Reactive Drop currently run on an engine build from 2020 due to a remote code execution exploit that was found.

If you have a system with a portrait monitor resolution, the first paragraph of this post is untrue.