It has been a long while I played this, but I'll return for the walkthrough to Ending 1
Thank you! Haha, I'm very curious about Ending 1
Okay... So here is the thing (LIGHT SPOILER):
a. (You'll recognize this map if you have finished Grey Plague at least once. I am not too diligent like some game tester out there to check the log and code behind this novel, but here is what I tried to get back to Ending 1... and failed :'D )
Failed Attempt 1: I thought that being nice, checking every people's condition, healing them etc and not getting any medicine just lead me to Ending 2. With that in mind, I deliberately didn't act nice, not using my power on any plagued people; but the narration insisted on me to use the power on my Grandma although I had no experience of using it at the lesser case! Not surprisingly, I got on Ending 2. I concluded that my interactions with others before going to Poor District didn't affect Grandma nor the endings.
Failed Attempt 2: Next, I tried on the combination of the medicine. The Apartement really functioned as a checkpoint where you could go back to refill your pocket and have enough money to buy the medicine.The wrong combination (especially using Microcube) got her worse,but the right combination (buying three kind of pills that suggested by the doctor at the hospital) was only told as something like "she seems getting better and her eyes twitches". Giving the medicine cautiously or indicating overdose also didn't affect anything, I was led to shake her body or finally calling Mom. Welcome me to Ending 2, again.
Failed Attempt 3: Regarding those two attempts. I guessed I had to prioritize Grandma. I tried to skip any choices that hinder my immediate way to Grandma's house, so I only moved from the mall to apartment to gain enough money to buy the medicine and not buying any breakfast for Mom. I was instructed to greet my friend first before I could go into the bus. However.... when I went straight away to Poor District, I couldn't pass into her house as the narration said such a thing "I need to complete my Mom's mission". It got worse as the game made me stuck to that scene in front of Grandma's house, because I couldn't click back to the bus nor click into the house. This is hella divine intervention working out there (or bugs.... mostly bugs xD)
b. ....It is more likely my memory alternating the reality, so forgive me for the miscommunication and my past claim of achieving Ending 1 ^^;
c. This bugs might be not fixed, as this VN would be traced back to the creator's project 2 years ago and the content seems more focused to the educational part (in my case, how much time or how perfect I played the cell simulation also didn't affect the overall plot) rather than chasing both endings of the story. I choose to assume that "hidden" Ending 1 is intentional enough to keep the player wondering "there must be another way to save my grandma" or accepting that the Grandma's condition had been already beyond critical (regarding the memory loss, the age, and the severity of her lungs); and like most of Angela He's previous works, it leads to the premise of "letting go". Moreover, with the most modern tools in medic, you don't mess up with brain that easily, also bring up the dilemma of having power and its consequences in acting heroic.
P.S. I just realize the significant of Red, Grandma, and the Grey Plague can be interpreted as medical version of Red Riding Hood ("grey" like the fur of a wolf and the plague that haunts the society...).