Shovel Knight: Treasure Trove

I beat the game in 1:09:32 while also getting the 'Beeline' and 'Naked King' achievements. During my playthrough I didn't buy any heirlooms, health upgrades or vigor upgrades.

However, you can buy armors. The Lightweight plate allows you to run faster but will cost you 6500 coins. You will have to finish some levels before you'll be able to buy it. (Credits to DubstepEdgelord)

Make sure to always have a backup save before attempting the next level. When you screw up just exit the game and make a copy of your backup save and try again until you got a good time.

These were my times after each map

Pridemor Kingdom - 0:12:06
Troupple Kingdom - 0:27:22
Birder Kingdom - 0:45:19
Finish - 1:09:32

You can skip all dialogues by pressing the start button. Also note that whenever there is a cutscene where you return to the airship, you can exit back to the map through the menu instead of walking out of the airship. This saves you a couple of seconds each time. You won't have to play a single game of Joustus but you will have to enter 'The House of Joustus' in order to continue the game. Once you enter the level you can immediately exit again. By the time that I reached the final boss stage I was at 0:59:39, which gave me enough time to fail a couple of times when beating the 3 bosses as they are pretty tough. Also if you have enough time left and you don't go for the 'Naked King' achievement, return to the airship to stock up on health and vigor upgrades.