ESPER system requirements state that you will need at least 8 GB of RAM. An Intel Core i5-6400 CPU is required at a minimum to run ESPER. However, the developers recommend a CPU greater or equal to an AMD Ryzen 5 2600 to play the game. Provided that you have at least an NVIDIA GeForce GTX 970 graphics card you can play the game. Futhermore, an NVIDIA GeForce GTX 1070 is recommended in order to run ESPER with the highest settings. In terms of game file size, you will need at least 520 MB of free disk space available.
ESPER will run on PC system with Windows 7 SP1 and upwards.