There can't be any viruses, since the program is self-written. It uses low-level winAPI calls, so it is often mistaken for all sorts of trojans, since similar mechanisms underlie the writing of viruses. Whether to use it or not is your right.
What is the command to change the number of hearts?
store.persistent.hearts_actual = xxx (xxx, number of red hearts)
store.persistent.ghearts_actual = xxx (xxx, number of yellow hearts)
"xxx" can be set, for example 1000000
The current value can be found by entering the command without a parameter, the equal sign is not needed.