In Cheat Engine, you can scan the game's memory for specific values (e.g., your current health).

While newer versions have speedhacks and advanced pointer scanners, version 5.4 still includes:

Cheat Engine 5.4 is a legacy version of the open-source game modification tool, originally released on January 1, 2008

It opens almost instantly and scans older games rapidly. Cheat Engine 5.4 Download Free PC: Safe Sources

For ethical game modification, stick to Cheat Engine 7.5+ – it is free, safe, and far more powerful.