I never got under 5min trying it the normal way (skill issue), but found this funny exploit when playing around with the shields.
The Sentinel Exploit For Easy Win
I’m sure there are other builds that work just as well/better, but this is what I used:
- 1 point in upper cannons
- 1 point in axe
- 1 point in star
- 1 point in shields
- 1 point in 2x speed (obviously not required, but faster)
Starting the game
Now instead of spending/skipping your remaining points, click on one of the shields.
The game will start, the upgrade window will stay and the balloons won’t gain hp.
Once the upgrade bar is full the game will pause again, expecting you to upgrade/skip.
Instead, click the shield again. The cycle will continue and the balloons will stay at 2hp.
Once the timer goes under 20 seconds spend all remaining points, just to clear the screen.
Wait for all remaining balloons to vanish. Wow, you beat the game (amazing).