MacReady did not become The Thing in the game. Despite the ambiguity surrounding his character in the film, the game makes it clear that MacReady is still alive and human. This is evident when he appears in a helicopter near the end of the game to help the player character.
Throughout the game, there are several moments where the player is left wondering if MacReady has been infected by The Thing. However, these moments are intentionally designed to create suspense and uncertainty, keeping the player on edge. The game cleverly plays with the idea of trust and paranoia, making it difficult to determine who is truly human and who has been assimilated by The Thing.
The fact that MacReady shows up in the helicopter as himself and assists the player character in fighting off a massive Thing creature further reinforces the idea that he is not The Thing. If he were infected, it is highly unlikely that he would be able to maintain his human form and consciousness, let alone help the player.
It’s worth noting that the game does include other characters who are revealed to be imposters and have been assimilated by The Thing. These characters try to deceive the player and blend in with the group, adding to the overall atmosphere of suspicion and paranoia. However, MacReady is not one of them.
In terms of gameplay, the player character can trust MacReady and rely on him for support. He provides valuable assistance during the final battle and helps the player defeat the monstrous Thing creature. This would not be possible if he had become The Thing himself.
While there may be moments of doubt and uncertainty surrounding MacReady’s character in the game, he ultimately proves himself to be human and allies with the player against The Thing. So, MacReady does not become The Thing in the game.