I recently got myself into short forms RPG as a GM and I really love the potential! I tried a short game (3 hours) and it went OK, but I am not quite satisfied yet. I need more practice, that's for sure, but there are parts where I don't know how to improve, and that's where I need your help.
The system I'm using is a personal design by myself and my group, not an established system. It has quick rules, a d20 for actions (with a consistent but not fixed outcome), and a lot of improvisation and flexibility from the GM. World is realist, but not too much: quite like an action movie, so if jumping though a window adds to the scene, only a bit of damage will be done.
A specific problem: a fast paced pursuit (20-25 min)
In one of the scenes of my game the PCs met a enemy NPC with valuable information. The NPC managed to get away and fled into the city.
I wanted this scene to be as great as pursuit scenes from action movies—fast paced, intense, challenging, leaving them short on breath in real life.
My approach: 1 minute hourglass, 1d20 for actions
I give a brief description of the scene to the group, turn the hourglass, let them decide what they do, and when the minute is over I move game time forward (e.g., make the NPC run, or attack them while fleeing).
Outcome: The feeling of being in a hurry worked well at the beginning, but they adapted by giving really short actions ("I run", "I jump", "I attack").
Reaction: As it was boring I decided to let them describe their actions more ("How?")
Outcome #2: More creative answers, less boring, but we totally lost the rhythm and it became a turn-by-turn RPG scene, definitely not what I intended.
I feel the group can manage to be creative while being stressed but as a GM I wasn't able to obtain the scene I wanted. How can I get the best of both worlds: fast paced action scenes and creative actions from the group? Props (a clock, time-tokens?), techniques (words, tone?) or just more practice?