less intrusive notifications, if possible...
When the notifications pop up, they fill the whole screen, blocking whatever you were in the middle of doing.
Is there any way for your app to notice if the screen or an app is currently being used, so that it doesn't overlay the screen and interfere? (For example, if someone was trying to call 911, and a bunch of notification started popping up, their phone would be blocked from access to calling 911 for many MINUTES as the screen was blocked, and their memory was plugged up preventing them from quickly getting access to the dialer.)
Your app could make the notification sound in the background and in the top reminder notification mini-bar, but not pop up to take over the full screen until the screen has not been touched for at least 3 to 5 seconds (or preferably a user-defined delay). Similarly, your app your app could include the ability for users to tell your app which apps to not overlay, but to wait until they are closed.
Another option, would be to have the reminder to take up only a portion of the screen, again with the user being able to set which portion of the screen (think of Messenger's movable Chat Heads). When they are ready to, the user can then tap the notification to open the full notification overlay and select the snooze options. And/or your chat-head style notification could have the option on the top half of it to do the default snooze and on the bottom half to open the full notification (or vice versa for the halves).
I had numerous reminders pop up just posting this, not only commandeering my phone, so to speak, while I was in the middle of something, but also jumping me out of each app I was in and working on, making me restart time, including the very message I typed above. So I had to keep copying and recopying as I added, so as to not keep losing it all.