I divide my time up into 15 minute intervals. But Google Calendar seems to want to treat all my reminders as needing 30 minutes to display, even if they are spaced 15 minutes apart, resulting in half of each reminder overlapping on the previous which cuts the horizontal space for each in half as show in the screen shot below:
As you can see, I can't even read what each reminder is for! I have gone to Settings and under "Event settings" I have set the default duration to 15 minutes. This seems to be the only relevant setting.
On Android I can zoom in and out by pinch to zoom, but this is never enough to let each task have it's own line. In a browser, the only way I can figure to zoom in and out is to alter the browser's zoom factor, and this also does not achieve the desired effect.
If it makes any difference, the same thing happens with events, but I only use events for things that are at least half an hour in length.